Antennas for 100 Pound DXpeditions
Computer-based antenna modeling and direct experience with
lightweight portable antenna systems
Volume 1: Selected high band antennas [20-6m]
B. Scott Andersen
NE1RD
ANTENNAS FOR 100 POUND DXPEDITIONS
White Paper – Version 1.01
Copyright 2007-2008 B. Scott Andersen
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ANTENNAS FOR 100 POUND DXPEDITIONS
TABLE OF CONTENTS
1
THE 100 POUND DXPEDITION................................................................................ 1
2
ANTENNA ASPECTS OF DXPEDITIONING ............................................................ 2
3
SOME NOTES ON MODELING ................................................................................ 5
4
PHYSICAL MEASUREMENT.................................................................................... 6
5
REFERENCE ANTENNAS........................................................................................ 7
5.1 Quarter-wave verticals ..........................................................................................................................7
5.1.1 10 meter Quarter-wave Vertical with Radials ..............................................................................7
5.1.2 12 meter Quarter-wave Vertical with Radials ............................................................................12
5.1.3 15 meter Quarter-wave Vertical with Radials ............................................................................15
5.1.4 17 meter Quarter-wave Vertical with Radials ............................................................................18
5.1.5 20 meter Quarter-wave Vertical with Radials ............................................................................21
5.2 Half-wave vertical dipoles ...................................................................................................................24
5.2.1 Full-sized 10 Meter Vertical Dipole.............................................................................................24
5.2.2 Full-sized 12 Meter Vertical Dipole.............................................................................................27
5.2.3 Full-sized 15 Meter Vertical Dipole.............................................................................................30
5.2.4 Full-sized 17 Meter Vertical Dipole.............................................................................................33
5.2.5 Full-sized 20 Meter Vertical Dipole.............................................................................................36
6
FORCE-12 SIGMA-5 ANTENNA............................................................................. 39
6.1 Force-12 Sigma-5 on 10 meters ........................................................................................................39
6.1.1 Model description ........................................................................................................................42
6.1.2 Analysis ........................................................................................................................................45
6.2 Force-12 Sigma-5 matching coil calculations....................................................................................47
6.3 Force-12 Sigma-5 on 12 meters ........................................................................................................48
6.4 Force-12 Sigma-5 on 15 meters ........................................................................................................51
6.5 Force-12 Sigma-5 on 17 meters ........................................................................................................53
6.6 Force-12 Sigma-5 on 20 meters ........................................................................................................54
7
TW ANTENNAS TW2010 TRAVELER ................................................................... 57
7.1
7.2
7.3
7.4
7.5
7.6
8
TW Antennas TW2010 Traveler on 10 meters .................................................................................57
TW Antennas TW2010 Traveler matching coil calculations.............................................................62
TW Antennas Traveler on 12 meters .................................................................................................64
TW Antennas Traveler on 15 meters .................................................................................................68
TW Antennas Traveler on 17 meters .................................................................................................71
TW Antennas Traveler on 20 meters .................................................................................................75
STANDARD BUDDIPOLE ...................................................................................... 80
8.1 Buddipole Horizontal Dipole ...............................................................................................................83
8.1.1 Buddipole Horizontal Dipole for 10-meters at 8 feet .................................................................83
8.1.2 Buddipole Horizontal Dipole for 10-meters at 16 feet ...............................................................86
8.1.3 Buddipole Horizontal Dipole for 12-meters at 16 feet ...............................................................89
8.1.4 Buddipole Horizontal Dipole for 15-meters at 16 feet ...............................................................92
8.1.5 Buddipole Horizontal Dipole for 17-meters at 16 feet ...............................................................95
8.2 Buddipole Vertical with L-arm radial at 8 feet....................................................................................98
8.2.1 Buddipole Vertical with L-arm radial for 10m at 8 feet ..............................................................98
8.2.2 Buddipole Vertical with L-arm radial for 12m at 8 feet ............................................................101
8.2.3 Buddipole Vertical with L-arm radial for 15m at 8 feet ............................................................104
ANTENNAS FOR 100 POUND DXPEDITIONS
8.2.4 Buddipole Vertical with L-arm radial for 17m at 8 feet ............................................................108
8.2.5 Buddipole Vertical with L-arm radial for 20m at 8 feet ............................................................111
8.3 Buddipole Vertical with L-arm radial at 16 feet ...............................................................................114
8.3.1 Buddipole Vertical with L-arm radial for 10m at 16 feet ..........................................................114
8.3.2 Buddipole Vertical with L-arm radial for 12m at 16 feet ..........................................................117
8.3.3 Buddipole Vertical with L-arm radial for 15m at 16 feet ..........................................................120
8.3.4 Buddipole Vertical with L-arm radial for 17m at 16 feet ..........................................................123
8.3.5 Buddipole Vertical with L-arm radial for 20m at 16 feet ..........................................................126
8.4 Buddipole vertical with single sloping radial at 16 feet ...................................................................129
8.4.1 Buddipole vertical with 1 radial for 10m at 16 feet ..................................................................129
8.4.2 Buddipole vertical with 1 radial for 12m at 8 feet ....................................................................132
8.4.3 Buddipole vertical with 1 radial for 15m at 8 feet ....................................................................135
8.4.4 Buddipole vertical with 1 radial for 17m at 16 feet ..................................................................138
8.4.5 Buddipole vertical with 1 radial for 20m at 16 feet ..................................................................141
9
LONG BUDDIPOLE .............................................................................................. 144
9.1 Differences between the Standard Buddipole and Long Buddipole ..............................................144
9.2 Buddipole full-sized vertical with 1 radial 8 feet ..............................................................................144
9.2.1 Buddipole full-sized vertical with 1 radial for 10m at 8 feet ....................................................144
9.2.2 Buddipole full-sized vertical with 1 radial for 12m at 8 feet ....................................................148
9.2.3 Buddipole full-sized vertical with 1 radial for 15m at 8 feet ....................................................151
9.2.4 Buddipole full-sized vertical with 1 radial for 17m at 8 feet ....................................................154
9.2.5 Buddipole full-sized vertical with 1 radial for 20m at 8 feet ....................................................157
9.3 Buddipole full-sized vertical with 4 radials at 8 feet ........................................................................160
9.3.1 Buddipole full-sized vertical with 4 radials for 10m at 8 feet ..................................................160
9.3.2 Buddipole full-sized vertical with 4 radials for 12m at 8 feet ..................................................163
9.3.3 Buddipole full-sized vertical with 4 radial for 15m at 8 feet ....................................................166
9.3.4 Buddipole full-sized vertical with 4 radials for 17m at 8 feet ..................................................169
9.3.5 Buddipole full-sized vertical with 4 radials for 20m at 8 feet ..................................................172
9.4 Buddipole full-sized vertical with 1 radial at 16 feet ........................................................................175
9.4.1 Buddipole full-sized vertical with 1 radial for 10m at 16 feet ..................................................175
9.4.2 Buddipole full-sized vertical with 1 radial for 12m at 16 feet ..................................................178
9.4.3 Buddipole full-sized vertical with 1 radial for 15m at 16 feet ..................................................181
9.4.4 Buddipole full-sized vertical with 1 radial for 17m at 16 feet ..................................................184
9.4.5 Buddipole full-sized vertical with 1 radial for 20m at 16 feet ..................................................187
9.5 Buddipole comparisons and conclusions ........................................................................................190
9.5.1 Gain and take-off angles of configurations ..............................................................................190
9.5.2 Comparing Buddipole to Force-12 Sigma-5 ............................................................................191
10
SMALL ANTENNAS 10-20M CONCLUSIONS ................................................... 197
11
THE EFFECTS OF GROUND ............................................................................. 199
11.1
11.2
11.3
12
Long ground radials for the Force-12 Sigma-5 .............................................................................199
The effects of radial length on a vertical dipole.............................................................................204
Dual-length radials ..........................................................................................................................208
BALCONY ANTENNAS ...................................................................................... 212
12.1 Problem description ........................................................................................................................212
12.2 20 meters .........................................................................................................................................212
12.2.1 Fishing pole horizontal antenna .............................................................................................212
13
ANTENNAS FOR 6M .......................................................................................... 217
13.1
14
Hentenna from the Buddipole Users Group ..................................................................................217
FINAL COMMENTS TO VOLUME 1 ................................................................... 221
ANTENNAS FOR 100 POUND DXPEDITIONS
APPENDIX A BUDDIPOLE COIL INDUCTANCES.................................................... 223
BUDDIPOLE LOW BAND COILS............................................................................... 224
REFERENCES............................................................................................................ 225
ANTENNAS FOR 100 POUND DXPEDITIONS
LIST OF FIGURES
Figure 1 AntennaSmith by Time Wave ..............................................................................................................6
Figure 2 On-screen plots viewed on the AntennaSmith ...................................................................................6
Figure 3 Full-sized 10m quarter-wave vertical ..................................................................................................8
Figure 4 SWR for quarter wave vertical on 12m ...............................................................................................9
Figure 5 Quarter wave vertical on 10m over good ground .............................................................................10
Figure 6 Quarter wave vertical on 10m over poor ground ..............................................................................10
Figure 7 Full-sized 12m quarter-wave vertical ................................................................................................12
Figure 8 SWR for quarter wave vertical on 12m .............................................................................................13
Figure 9 Quarter wave vertical on 12m over good ground .............................................................................14
Figure 10 Quarter wave vertical on 12m over poor ground ............................................................................14
Figure 11 Full-sized 15m quarter-wave vertical ..............................................................................................15
Figure 12 SWR for quarter wave vertical on 15m ...........................................................................................16
Figure 13 Quarter wave vertical on 15m over good ground ...........................................................................17
Figure 14 Quarter wave vertical on 15m over poor ground ............................................................................17
Figure 15 Full-sized 17m quarter-wave vertical ..............................................................................................18
Figure 16 SWR for quarter wave vertical on 17m ...........................................................................................19
Figure 17 Quarter wave vertical on 17m over good ground ...........................................................................20
Figure 18 Quarter wave vertical on 17m over poor ground ............................................................................20
Figure 19 Full-sized 20m quarter-wave vertical ..............................................................................................21
Figure 20 SWR for quarter wave vertical on 20m ...........................................................................................22
Figure 21 Quarter wave vertical on 20m over good ground ...........................................................................23
Figure 22 Quarter wave vertical on 20m over poor ground ............................................................................23
Figure 23 View of the full-sized 10 meter vertical dipole ................................................................................24
Figure 24 SWR for half wave vertical dipole on 10m ......................................................................................25
Figure 25 Half-wave vertical dipole on 10m over good ground......................................................................26
Figure 26 Half-wave vertical dipole on 10m over poor ground.......................................................................27
Figure 27 View of the full-sized 12 meter vertical dipole ................................................................................27
Figure 28 SWR for half wave vertical dipole on 12m ......................................................................................28
Figure 29 Half-wave vertical dipole on 12m over good ground......................................................................29
Figure 30 Half-wave vertical dipole on 12m over poor ground.......................................................................29
Figure 31 View of the full-sized 15 meter vertical dipole ................................................................................30
Figure 32 SWR for half wave vertical dipole on 15m ......................................................................................31
Figure 33 Half-wave vertical dipole on 15m over good ground......................................................................32
Figure 34 Half-wave vertical dipole on 15m over poor ground.......................................................................32
Figure 35 View of the full-sized 17 meter vertical dipole ................................................................................33
Figure 36 SWR for half wave vertical dipole on 17m ......................................................................................34
Figure 37 Half-wave vertical dipole on 17m over good ground......................................................................35
Figure 38 Half-wave vertical dipole on 17m over poor ground.......................................................................35
Figure 39 View of the full-sized 20 meter vertical dipole ................................................................................36
Figure 40 SWR for half wave vertical dipole on 20m ......................................................................................37
Figure 41 Half-wave vertical dipole on 20m over good ground......................................................................38
Figure 42 Half-wave vertical dipole on 20m over poor ground.......................................................................38
Figure 43 The assembled Force-12 Sigma-5 ..................................................................................................40
Figure 44 Force-12 Sigma-5 matching circuit..................................................................................................41
Figure 45 Force-12 Sigma-5 element diameters.............................................................................................42
Figure 46 EZNEC antenna view of Sigma-5....................................................................................................45
Figure 47 SWR for Force-12 Sigma-5 on 10 meters ......................................................................................45
Figure 48 Force-12 Sigma-5 on 10m over good ground ................................................................................46
Figure 49 Force-12 Sigma-5 on 10m over poor ground .................................................................................46
Figure 50 EL 10m quarter wave and vertical dipole over poor ground..........................................................47
Figure 51 SWR for Force-12 Sigma-5 on 12 meters ......................................................................................49
Figure 52 Force-12 Sigma-5 on 12m over good ground ................................................................................50
ANTENNAS FOR 100 POUND DXPEDITIONS
Figure 53 Force-12 Sigma-5 on 12m over poor ground .................................................................................50
Figure 54 SWR for Force-12 Sigma-5 on 15 meters ......................................................................................51
Figure 55 Force-12 Sigma-5 on 15m over good ground ................................................................................52
Figure 56 Force-12 Sigma-5 on 15m over poor ground .................................................................................52
Figure 57 SWR for Force-12 Sigma-5 on 17 meters ......................................................................................53
Figure 58 Force-12 Sigma-5 on 17m over good ground ................................................................................54
Figure 59 Force-12 Sigma-5 on 17m over poor ground .................................................................................54
Figure 60 SWR for Force-12 Sigma-5 on 20 meters ......................................................................................55
Figure 61 Force-12 Sigma-5 on 20m over good ground ................................................................................56
Figure 62 Force-12 Sigma-5 on 20m over poor ground .................................................................................56
Figure 63 TW Antennas Traveler model view .................................................................................................58
Figure 64 SWR for TW Antennas Traveler on 10m ........................................................................................59
Figure 65 TW Antennas Traveler on 10m over good ground .........................................................................59
Figure 66 TW Antennas Traveler on 10m over poor ground..........................................................................60
Figure 67 AZ Sigma-5 and Traveler on 10m over good ground ....................................................................60
Figure 68 EL Sigma-5 and Traveler on 10m over good ground.....................................................................61
Figure 69 AZ Sigma-5 and Traveler on 10m over poor ground .....................................................................61
Figure 70 EL Sigma-5 and Traveler on 10m over poor ground......................................................................62
Figure 71 Measuring Traveler coils with Photoshop .......................................................................................63
Figure 72 SWR for TW Antennas Traveler on 12m ........................................................................................64
Figure 73 TW Antennas Traveler on 12m over good ground .........................................................................65
Figure 74 TW Antennas Traveler on 12m over poor ground..........................................................................65
Figure 75 AZ Sigma-5 and Traveler on 12m over good ground ....................................................................66
Figure 76 EL Sigma-5 and Traveler on 12m over good ground.....................................................................66
Figure 77 AZ Sigma-5 and Traveler on 12m over poor ground .....................................................................67
Figure 78 EL Sigma-5 and Traveler on 12m over poor ground......................................................................67
Figure 79 SWR for TW Antennas Traveler on 15m ........................................................................................68
Figure 80 TW Antennas Traveler over good ground.......................................................................................69
Figure 81 TW Antennas Traveler on 15m over poor ground..........................................................................69
Figure 82 AZ Sigma-5 and Traveler on 15m over good ground ....................................................................70
Figure 83 EL Sigma-5 and Traveler on 15m over good ground.....................................................................70
Figure 84 AZ Sigma-5 and Traveler on 15m over poor ground .....................................................................71
Figure 85 AZ Sigma-5 and Traveler on 15m over poor ground .....................................................................71
Figure 86 SWR for TW Antennas Traveler on 17m ........................................................................................72
Figure 87 TW Antennas Traveler on 17m over good ground .........................................................................73
Figure 88 TW Antennas Traveler on 17m over poor ground..........................................................................73
Figure 89 AZ Sigma-5 and Traveler on 17m over good ground ....................................................................74
Figure 90 EL Sigma-5 and Traveler on 17m over good ground.....................................................................74
Figure 91 AZ Sigma-5 and Traveler on 17m over poor ground .....................................................................75
Figure 92 EL Sigma-5 and Traveler on 17m over poor ground......................................................................75
Figure 93 SWR for TW Antennas Traveler on 20m ........................................................................................76
Figure 94 TW Antennas Traveler on 20m over good ground .........................................................................77
Figure 95 TW Antennas Traveler on 20m over poor ground..........................................................................77
Figure 96 AZ Sigma-5 and Traveler on 20m over good ground ....................................................................78
Figure 97 EL Sigma-5 and Traveler on 20m over good ground.....................................................................78
Figure 98 AZ Sigma-5 and Traveler on 20m over poor ground .....................................................................79
Figure 99 EL Sigma-5 and Traveler on 20m over poor ground......................................................................79
Figure 100Buddipole in the bag........................................................................................................................81
Figure 101 Buddipole on 10m at 8 feet............................................................................................................84
Figure 102 Buddipole horizontal dipole for 10m at 8 feet over good ground ................................................85
Figure 103 Buddipole horizontal dipole for 10m at 8 feet over poor ground .................................................85
Figure 104 SWR for Buddipole horizontal dipole for 10m at 16 feet..............................................................87
Figure 105 Buddipole horizontal dipole for 10m at 16 feet over good ground ..............................................88
Figure 106 Buddipole horizontal dipole for 10m at 16 feet over poor ground ...............................................88
Figure 107 Half-wave vertical dipole vs. Buddipole horizontal dipole for 10 meters ....................................89
ANTENNAS FOR 100 POUND DXPEDITIONS
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SWR for Buddipole horizontal dipole for 12m at 16 feet..............................................................90
Buddipole horizontal dipole for 12m at 16 feet over good ground ..............................................91
Buddipole horizontal dipole for 12m at 16 feet over poor ground ...............................................91
SWR for Buddipole horizontal dipole for 15m at 16 feet..............................................................93
Buddipole horizontal dipole for 15m at 16 feet over good ground ..............................................94
Buddipole horizontal dipole for 15m at 16 feet over poor ground ...............................................94
SWR for Buddipole horizontal dipole for 17m at 16 feet..............................................................96
Buddipole horizontal dipole for 17m at 16 feet over good ground ..............................................97
Buddipole horizontal dipole for 17m at 16 feet over poor ground ...............................................97
SWR for Buddipole vertical with L-radial on 10m at 8 feet ..........................................................99
Buddipole vertical with L-radial on 10m at 8 feet .......................................................................100
Buddipole vertical with L-radial on 10m at 8 feet over good ground.........................................100
Buddipole vertical with L-radial on 10m at 8 feet over poor ground .........................................101
Buddipole vertical with L-radial on 12m at 8 feet .......................................................................101
SWR for Buddipole vertical with L-radial on 12m at 8 feet ........................................................103
Buddipole vertical with L-radial on 12m at 8 feet over good ground.........................................103
Buddipole vertical with L-radial on 12m at 8 feet over poor ground .........................................104
Buddipole vertical with L-radial on 15m at 8 feet .......................................................................104
SWR for Buddipole vertical with L-radial on 15m at 8 feet ........................................................106
Buddipole vertical with L-radial on 15m at 8 feet over good ground.........................................107
Buddipole vertical with L-radial on 15m at 8 feet over poor ground .........................................107
Buddipole vertical with L-radial on 17m at 8 feet .......................................................................108
SWR for Buddipole vertical with L-radial on 17m at 8 feet ........................................................109
Buddipole vertical with L-radial on 17m at 8 feet over good ground.........................................110
Buddipole vertical with L-radial on 17m at 8 feet over poor ground .........................................110
Buddipole vertical with L-radial on 20m at 8 feet .......................................................................111
SWR for Buddipole vertical with L-radial on 20m at 8 feet ........................................................112
Buddipole vertical with L-radial on 20m at 8 feet over good ground.........................................113
Buddipole vertical with L-radial on 20m at 8 feet over poor ground .........................................113
Buddipole vertical with L-radial on 10m at 16 feet .....................................................................114
SWR for Buddipole vertical with L-radial on 10m at 16 feet ......................................................115
Buddipole vertical with L-radial on 10m at 16 feet over good ground.......................................116
Buddipole vertical with L-radial on 10m at 16 feet over poor ground .......................................116
Buddipole vertical with L-radial on 12m at 16 feet .....................................................................117
SWR for Buddipole vertical with L-radial on 12m at 16 feet ......................................................118
Buddipole vertical with L-radial on 12m at 16 feet over good ground.......................................119
Buddipole vertical with L-radial on 12m at 16 feet over poor ground .......................................119
Buddipole vertical with L-radial on 15m at 16 feet .....................................................................120
SWR for Buddipole vertical with L-radial on 15m at 16 feet ......................................................121
Buddipole vertical with L-radial on 15m at 16 feet over good ground.......................................122
Buddipole vertical with L-radial on 15m at 16 feet over poor ground .......................................122
Buddipole vertical with L-radial on 17m at 16 feet .....................................................................123
SWR for Buddipole vertical with L-radial on 17m at 16 feet ......................................................124
Buddipole vertical with L-radial on 17m at 16 feet over good ground.......................................125
Buddipole vertical with L-radial on 17m at 16 feet over poor ground .......................................125
Buddipole vertical with L-radial on 20m at 16 feet .....................................................................126
SWR for Buddipole vertical with L-radial on 20m at 16 feet ......................................................127
Buddipole vertical with L-radial on 20m at 16 feet over good ground.......................................128
Buddipole vertical with L-radial on 20m at 16 feet over poor ground .......................................128
Buddipole vertical for 10m with 1 radial ......................................................................................129
SWR for Buddipole vertical with 1 radial on 10m at 16 feet ......................................................130
Buddipole vertical with 1 radial on 10m at 16 feet over good ground.......................................131
Buddipole vertical with 1 radial on 10m at 16 feet over poor ground........................................131
Buddipole vertical for 12m with 1 radial ......................................................................................132
SWR for Buddipole vertical with 1 radial on 12m at 16 feet ......................................................133
Buddipole vertical with 1 radial on 12m at 16 feet over good ground.......................................134
ANTENNAS FOR 100 POUND DXPEDITIONS
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Buddipole vertical with 1 radial on 12m at 16 feet over poor ground........................................134
Buddipole vertical for 15m with 1 radial ......................................................................................135
SWR for Buddipole vertical with 1 radial on 15m at 16 feet ......................................................136
Buddipole vertical with 1 radial on 15m at 16 feet over good ground.......................................137
Buddipole vertical with 1 radial on 15m at 16 feet over poor ground........................................137
Buddipole vertical for 17m with 1 radial ......................................................................................138
SWR for Buddipole vertical with 1 radial on 17m at 16 feet ......................................................139
Buddipole vertical with 1 radial on 17m at 16 feet over good ground.......................................140
Buddipole vertical with 1 radial on 17m at 16 feet over poor ground........................................140
Buddipole vertical for 20m with 1 radial ......................................................................................141
SWR for Buddipole vertical with 1 radial on 20m at 16 feet ......................................................142
Buddipole vertical with 1 radial on 20m at 16 feet over good ground.......................................143
Buddipole vertical with 1 radial on 20m at 16 feet over poor ground........................................143
Buddipole full-sized vertical for 10m with 1 radial ......................................................................145
SWR for BP full-sized vertical with 1 radial on 10m at 8 feet ....................................................146
BP full-sized vertical with 1 radial on 10m at 8 feet over good ground.....................................147
Buddipole full-sized vertical, 1 radial on 10m at 8 feet over poor ground ................................147
Buddipole full-sized vertical for 12m with 1 radial ......................................................................148
SWR for BP full-sized vertical with 1 radial on 12m at 8 feet ....................................................149
BP full-sized vertical with 1 radial on 12m at 8 feet over good ground.....................................150
Buddipole full-sized vertical, 1 radial on 12m at 8 feet over poor ground ................................150
Buddipole full-sized vertical for 15m with 1 radial ......................................................................151
SWR for BP full-sized vertical with 1 radial on 10m at 8 feet ....................................................152
BP full-sized vertical with 1 radial on 15m at 8 feet over good ground.....................................153
Buddipole full-sized vertical, 1 radial on 15m at 8 feet over poor ground ................................153
Buddipole full-sized vertical for 17m with 1 radial ......................................................................154
SWR for BP full-sized vertical with 1 radial on 17m at 8 feet ....................................................155
BP full-sized vertical with 1 radial on 10m at 8 feet over good ground.....................................156
Buddipole full-sized vertical, 1 radial on 17m at 8 feet over poor ground ................................156
Buddipole full-sized vertical for 20m with 1 radial ......................................................................157
SWR for BP full-sized vertical with 1 radial on 20m at 8 feet ....................................................158
BP full-sized vertical with 1 radial on 20m at 8 feet over good ground.....................................159
Buddipole full-sized vertical, 1 radial on 20m at 8 feet over poor ground ................................159
Buddipole full-sized vertical for 10m with 4 radials ....................................................................160
SWR for BP full-sized vertical with 4 radials on 10m at 8 feet ..................................................161
BP full-sized vertical with 4 radials on 10m at 8 feet over good ground...................................162
Buddipole full-sized vertical, 4 radials on 10m at 8 feet over poor ground ..............................162
Buddipole full-sized vertical for 12m with 4 radials ....................................................................163
SWR for BP full-sized vertical with 4 radial on 12m at 8 feet ....................................................164
BP full-sized vertical with 4 radial on 12m at 8 feet over good ground.....................................165
Buddipole full-sized vertical, 4 radials on 12m at 8 feet over poor ground ..............................165
Buddipole full-sized vertical for 15m with 4 radials ....................................................................166
SWR for BP full-sized vertical with 4 radials on 10m at 8 feet ..................................................167
BP full-sized vertical with 4 radials on 15m at 8 feet over good ground...................................168
Buddipole full-sized vertical, 4 radials on 15m at 8 feet over poor ground ..............................168
Buddipole full-sized vertical for 17m with 4 radials ....................................................................169
SWR for BP full-sized vertical with 4 radials on 17m at 8 feet ..................................................170
BP full-sized vertical with 4 radials on 10m at 8 feet over good ground...................................171
Buddipole full-sized vertical, 4 radials on 17m at 8 feet over poor ground ..............................171
Buddipole full-sized vertical for 20m with 4 radials ....................................................................172
SWR for BP full-sized vertical with 4 radials on 20m at 8 feet ..................................................173
BP full-sized vertical with 4 radials on 20m at 8 feet over good ground...................................174
Buddipole full-sized vertical, 4 radials on 20m at 8 feet over poor ground ..............................174
Buddipole full-sized vertical for 10m with 1 radial ......................................................................175
SWR for BP full-sized vertical with 1 radial on 10m at 16 feet..................................................176
ANTENNAS FOR 100 POUND DXPEDITIONS
Figure 219 BP full-sized vertical with 1 radial on 10m at 16 feet over good ground ..................................177
Figure 220 Buddipole full-sized vertical, 1 radial on 10m at 16 feet over poor ground ..............................177
Figure 221 Buddipole full-sized vertical for 12m with 1 radial ......................................................................178
Figure 222 SWR for BP full-sized vertical with 1 radial on 12m at 16 feet..................................................179
Figure 223 BP full-sized vertical with 1 radial on 12m at 16 feet over good ground ..................................180
Figure 224 Buddipole full-sized vertical, 1 radial on 12m at 16 feet over poor ground ..............................180
Figure 225 Buddipole full-sized vertical for 15m with 1 radial ......................................................................181
Figure 226 SWR for BP full-sized vertical with 1 radial on 10m at 16 feet ..................................................182
Figure 227 BP full-sized vertical with 1 radial on 15m at 16 feet over good ground ..................................183
Figure 228 Buddipole full-sized vertical, 1 radial on 15m at 16 feet over poor ground ..............................183
Figure 229 Buddipole full-sized vertical for 17m with 1 radial ......................................................................184
Figure 230 SWR for BP full-sized vertical with 1 radial on 17m at 16 feet..................................................185
Figure 231 BP full-sized vertical with 1 radial on 10m at 16 feet over good ground ..................................186
Figure 232 Buddipole full-sized vertical, 1 radial on 17m at 16 feet over poor ground ..............................186
Figure 233 Buddipole full-sized vertical for 20m with 1 radial ......................................................................187
Figure 234 SWR for BP full-sized vertical with 1 radial on 20m at 16 feet..................................................188
Figure 235 BP full-sized vertical with 1 radial on 20m at 16 feet over good ground ..................................189
Figure 236 Buddipole full-sized vertical, 1 radial on 20m at 16 feet over poor ground ..............................189
Figure 237 Force-12 Sigma-5 vs. BP full-sized vertical on 10m azimuth....................................................192
Figure 238 Force-12 Sigma-5 vs. BP full-sized vertical on 10m elevation ..................................................192
Figure 239 Force-12 Sigma-5 vs. BP full-sized vertical on 12m azimuth....................................................193
Figure 240 Force-12 Sigma-5 vs. BP full-sized vertical on 12m elevation ..................................................193
Figure 241 Force-12 Sigma-5 vs. BP full-sized vertical on 15m azimuth....................................................194
Figure 242 Force-12 Sigma-5 vs. BP full-sized vertical on 15m elevation ..................................................194
Figure 243 Force-12 Sigma-5 vs. BP full-sized vertical on 17m azimuth....................................................195
Figure 244 Force-12 Sigma-5 vs. BP full-sized vertical on 17m elevation ..................................................195
Figure 245 Force-12 Sigma-5 vs. BP full-sized vertical on 20m azimuth....................................................196
Figure 246 Force-12 Sigma-5 vs. BP full-sized vertical on 20m elevation ..................................................196
Figure 247 Comparing various 20m antenna options ...................................................................................197
Figure 248 Force-12 Sigma-5 on 20m over a range of ground types..........................................................200
Figure 249 Full-wave radials used to reduce ground loss ............................................................................201
Figure 250 Force-12 Sigma-5 on 10m compares no radials and 16 radials ...............................................202
Figure 251 Force-12 Sigma-5 on 12m compares no radials and 16 radials ...............................................202
Figure 252 Force-12 Sigma-5 on 15m compares no radials and 16 radials ...............................................203
Figure 253 Force-12 Sigma-5 on 17m compares no radials and 16 radials ...............................................203
Figure 254 Varying radial lengths for 16 radials over a vertical dipole ........................................................205
Figure 255 Varying radial length for 32 radials over a vertical dipole..........................................................206
Figure 256 Radial length vs. gain for 16 radials under a Force-12 Sigma-5...............................................208
Figure 257 16 radials alternating lengths of 20 feet and 33 feet under Force-12 Sigma-5........................209
Figure 264 Cabela’s 14 foot collapsible panfish pole....................................................................................213
Figure 265 Balcony fishing pole antenna for 20m.........................................................................................214
Figure 266 SWR for 20m fishing pole balcony antenna ...............................................................................215
Figure 267 20m fishing pole balcony antenna 2D far field pattern...............................................................216
Figure 268 20m fishing pole balcony antenna 3D far field pattern...............................................................216
Figure 269 Hentenna for 6m antenna view....................................................................................................217
Figure 270 Hentenna for 6m SWR .................................................................................................................218
Figure 271 6m Hentenna Far Field Plot (3D) ................................................................................................219
Figure 272 Hentenna for 6m Far Field Plot over good ground.....................................................................220
Table 1 Force-12 Sigma-5 loading coil values ................................................................................................48
Table 2 TW Antenna Traveler coil values ........................................................................................................63
Table 3 Recipes for Buddipole dipole configurations......................................................................................82
Table 4 Buddipole gain and take-off angle summary....................................................................................190
Table 5 Force-12 Sigma-5 gain comparisons 16 67-foot radials vs. no radials ..........................................204
Table 6 Force-12 Sigma-5 gain comparisons 16 33-foot radials vs. no radials ..........................................206
ANTENNAS FOR 100 POUND DXPEDITIONS
Table 7 Force-12 Sigma-5 computed gains with 16 radials of varying length ............................................207
Table 8 Relative gain (dB) of Force-12 Sigma-5 over 16 radials of various lengths ..................................207
Table 9 Comparing gains for the 16@33-feet and 8@20-feet + 8@33-feet configurations ......................209
Table 10 Comparing gains for the 16@33-feet and 8@24-feet + 8@33-feet configurations ....................211
ANTENNAS FOR 100 POUND DXPEDITIONS
1 THE 100 POUND DXPEDITION
A DXpedition is an expedition for the purpose of communicating long distances with
amateur radio (often called DX). The idea of such an adventure is at least 60 years old
dating back to the Kon Tiki, the raft used by Norwegian explorer and writer Thor Heyerdahl
in his 1947 expedition across the Pacific ocean from South America to Polynesia. That
simple QRP transmitter helped the crew keep in contact with civilization throughout their
101 day voyage.
Danny Weil (VP2VB), inspired by the Kon Tiki adventure, was one of the DXpeditioning
pioneers making contact with over 100,000 hams around the world on his various trips in his
boats YASME and YASME II. The YASME Foundation now assists DXers and
DXpeditioners alike by funding scientific and educational projects relating to amateur radio.
Since Danny Weil’s time there have been significant advances in technology and
DXpeditioning strategies. The “one man in a boat” has been replaced by cargo containers
filled with radios, antennas, computers, coax, and many tons of other equipment.
DXpedition teams of 10 to 30 operators are not uncommon. While this has been a boon to
those looking for a contact from remote places like Peter I, South Sandwich Island, or
Kerguelen, the enormous price-tag associated with such endeavors put it out of reach for all
but the most affluent or famous.
The 100 Pound DXpedition is my answer to this situation. It is a return to basics. The idea is
this: with just 100 pounds of equipment, one should be able to set up on some far away place
and operate a DXpedition. This weight limit imposes an upper-bound on what can be done.
For example, some of the larger DXpeditions try to separate antennas by 1000 or 1200 feet.
The weight of 1000 foot of RG-213 coax is about 104 pounds—four pounds over the limit
for all equipment on a 100 Pound DXpedition!
As artists sometimes say, “Form is freeing.” That is to say that limits help bring focus and
illuminate possibilities. With such draconian weight limits you cannot be tempted to bring
the big amplifier, tower sections, or huge antennas. Instead, you can begin to research
compromises and trade-offs, see what works and what does not, and determine for yourself
what is key, what is extra, what is signal and what is noise. In a permanent station you might
fight for every dB. But, when every pound counts, do you trade 2 dB for 12 extra pounds?
These thinking processes are at the very heart of a 100 Pound DXpedition.
Finally, with these limits come rewards. Traveling so light means you and your portable
station are just a plane ride away from very interesting places. The 100 pound limit fits
within many airline guidelines so a DXpedition can be done by packing, checking your
bags, and finding your seat. There are no cargo containers. There are no tedious logistics and
freight plans. You can just go, unpack, set up, and have fun.
The remainder of this white paper discusses the antenna aspects of a 100 Pound DXpedition.
Again, we are not looking for the biggest and best; we are looking for the best “bang for our
buck” and best “power per pound.” Welcome to lightweight DXpeditioning.
1
ANTENNAS FOR 100 POUND DXPEDITIONS
2 ANTENNA ASPECTS OF DXPEDITIONING
Preparing an antenna for your home station may involve weeks or months of planning and
execution. Erecting a tower, for example, may involve obtaining permits from your
community’s planning board, digging the footing, filling it with rebar and concrete, and
waiting a month for that concrete to cure. Only then can you attach the tower and begin
thinking about hoisting the antennas to height.
The weight of an antenna system for a home station is rarely of concern except perhaps for
the shipping charges for the delivery of the parts. Heavy tower sections or antennas are a
minor inconvenience if they require extra hands during assembly. And, once a system is
assembled we are rarely interested in how easily it can be disassembled and shipped again.
Antennas for DXpeditioning violate many of the assumptions that we might have for
antennas in our home station. We care about their weight. We care about assembly and
disassembly time and complexity. The antennas must be assembled, disassembled, and
shipped repeatedly for us to get value from them.
Put more starkly: it doesn’t matter if an antenna performs well if you can’t bring it.
Antennas that are too heavy, too complicated, require hefty support structures, or cannot be
broken into small (48 inch) pieces cannot be considered for this use. If you plan a trip for a
week to some beautiful destination, you cannot afford to spend two days assembling
antennas and another disassembling them. Antennas that require that kind of investment
might make fine home station antennas, but they are all but useless for lightweight
DXpeditioning.
The baggage allowances set by airlines provide a general guideline for the physical
dimensions of the antennas we can consider. These allowances are typically:
•
Two checked bags. Some airlines allow three bags (such as Southwest), but the
general allowance is two bags for most US carriers. In this age of high fuel prices,
some carriers are now charging a fee for the second and even first checked bag. Still,
it is a reasonable assumption that two checked bags can be brought without excessive
charges.
•
Fifty pounds per bag. Some airlines are more lax on this point than others. You can
also pay to have your bag accepted for weights up to 70 or even 100 pounds. This is
helpful when you may be living within the 100 pound combined limit, but one bag is
heavier than another.
•
Size of 62 linear inches. The combined height plus width plus depth of a bag cannot
exceed 62 inches. The Pelican 1610 case is one of the largest cases that satisfies this
requirement.
•
Golf and sports bags. There is an exception to the above rules for sports enthusiasts,
or at least those of us who use similar equipment. Golf bags, ski bags, and similar
equipment bags are exempted from the size restriction and sometimes from the
weight restriction.
These are general guidelines. Check with your carrier for the specific rules of your airline.
2
ANTENNAS FOR 100 POUND DXPEDITIONS
A reasonable strategy is to have one hard-sided golf bag for long antenna parts, coax, and
other parts, and have a second hard-sided case for the radio, tuner, power supply, and other
smaller parts. A third carry-on bag can then hold clothes and other personal items.
Remember, you need to count the weight of the equipment and the weight of the bags when
budgeting!
Here are some things we look for when making antenna selection for lightweight
DXpeditions:
•
Size – This is even more important than weight in some respects. A golf bag will
typically accommodate pieces 48 inches in length. If it cannot fit in the bag, it cannot
go. So, even very light antennas with 72 inch parts (6 foot lengths) are not useful for
our purposes.
•
Weight – We have a total weight budget of 100 pounds but can divide this between
all the equipment in whatever fashion we like. If we wish to bring more radio gear,
we will likely need to bring fewer antenna pieces. Similarly, if we bring larger,
heavier, or bulkier antennas, we may have to bring fewer or lighter other items to
compensate. Weight is always a trade-off in these calculations.
•
Ease of assembly and disassembly – Some antennas are designed to be assembled
once and never disassembled. The use of pop-rivets would be an example of an
antenna design decision that would hint at this. The best lightweight DXpedition
antennas are ones that can be assembled easily, disassembled easily, and packed
easily. Custom bags, containers, and packing materials that would never see use for a
home station antenna can be extremely beneficial for a DXpedition antenna.
•
Multiple band use – This is not a requirement, but it can be very helpful to have an
antenna that is effective on multiple bands. There are two reasons for this:
o Multi-band antennas may reduce the deployment time for your antenna
systems. For example, if you assemble a 40m antenna that is also effective on
15m, this means you do not need to assemble a specific 15m antenna. Also,
trapped verticals or triband yagis provide multiple bands but may not be more
complicated or time-consuming to assemble than a similarly designed singleband antenna. The time savings can mean more operating or leisure time in
that exotic location.
o Multi-band antenna systems require only one run of coax – This is almost
trivial for home stations but quite important for a lightweight DXpedition. A
discussion of coax trade-offs may be found later in this paper.
•
The antenna’s physical footprint – Depending on your DXpedition’s destination,
there may not be much room to erect antennas. In such cases, antennas with smaller
footprints may be more desirable than larger ones. For example, a -wave vertical
requires radials. If there is no room to run these radials, however, you’ve got a
problem. A half-wave vertical dipole does not need radials and can be erected in a
very small area. Vertical dipoles have other disadvantages such as being taller (in
general) and more difficult to feed (since the feed point is higher and the feed line
must be routed carefully to avoid parasitic coupling).
3
ANTENNAS FOR 100 POUND DXPEDITIONS
•
The antenna’s visual footprint – Unless you are isolated from others, erecting large,
ugly antenna systems may be frowned upon by your neighbors. You will need to
select an antenna compliment that is “compatible with the neighborhood.”
The antennas discussed in this white paper conform to these guidelines to varying
degrees. Evaluating the antennas is not a straightforward task either for the criteria
above, or for performance in the field. Perhaps the criteria above can be used to provide
guidance as to whether an antenna is eligible for this service and other criteria can
determine its performance in this service.
Few things get amateur radio operators more wound-up than antenna performance
discussions. So, let me say this before anything else is presented:
Everything in this white paper is wrong to some degree.
In the sciences like physics and chemistry there is a notion of experimental error. The
experiment may be intentionally flawed to take advantage of significant simplifications.
Results may therefore be representative, but not numerically precise. There is also the
concept of measurement error. Even when precise measurements are taken there will
always be variations and precision limitations. There will be a great deal of both types of
errors in what follows. If this makes you uncomfortable, stop reading now.
I will be discussing antenna products and antenna designs that I have used, or considered
using, on lightweight DXpeditions. I have spent the last few years gathering practical
experience with these antennas and have now augmented that with computer models.
These models, although they use software that has a surprising mathematical precision,
are approximations of the actual antenna system. First, some antennas are described
using only approximate dimensions for element lengths, element diameters, materials, or
the placement of certain junctions. In some cases the imprecision is because these small
differences make the model much easier to construct or because of the limitations of the
modeling engine. Other justifications for this imprecision are more easy to explain: I do
not own the antenna in question and have made only guesses (though well-reasoned
guesses, to be sure) of some of the values. Finally, never discount the possibility that I
just measured wrong, entered the data wrong, or otherwise goofed.
Rather than defend every number abstractly I will discuss every choice and every
method used to create the models. I’ll show the results from the modeling and compare
it, where possible, to practical experience I have had with the antenna. I will also include
details of the model files so everyone can execute these models and check the inputs and
results for themselves. I have found this research to be helpful for my planning and my
trips. I hope they will be as helpful to others.
4
ANTENNAS FOR 100 POUND DXPEDITIONS
3 SOME NOTES ON MODELING
The following models were created with EZNEC 5 from W7EL. This is an extremely
powerful piece of software and I can only hope to master some of it over the next few years.
Luckily, my immediate needs for this analysis only require understanding the basics of the
program.
Antenna modeling software provides very accurate computations and results based on the
input it receives. That said, this software cannot overcome bad input. If the model is wrong,
the answer will likely be at least as wrong. But, to put this into perspective, consider these
words:
“Essentially, all models are wrong, but some are useful.”
George Box, Professor Emeritus of Statistics at the University of Wisconsin
There are some small compromises in the placement of antenna elements in these models
because of limitations in the modeling software. I believe the errors induced by these small
changes will not adversely affect the results. There are other small compromises in
measurements that have been made to make the models simpler (and the life of the modeler
easier). Again, I believe that these small compromises still provide modeling results that are
representative of the behavior and performance of the device modeled. The model
descriptions for each antenna contain notes that describe such compromises when they have
been made.
There are things that are difficult to specify. The effects of ground are quite important to
many antenna systems and yet this data is difficult to specify with any accuracy. To
accommodate this, I provide several runs of computation and output for both good ground
and very poor ground. An example of good ground is pastoral ground; an example of poor
ground is a city lot. EZNEC provides mappings of these concepts to numeric values used in
its calculations. The performance in any particular situation will likely be between those two
extremes
Finally, a model is not the thing you are modeling. I will, where possible, provide
completely subjective commentary relating to my experience with each antenna. As the
common modern day lament goes, “your mileage may vary.” Before we begin with some
antennas that we will use as “reference” antennas we shall have a brief discussion about
physical measurements.
5
ANTENNAS FOR 100 POUND DXPEDITIONS
4 PHYSICAL MEASUREMENT
Modeling was done with EZNEC. Direct measurements of some antenna systems were done
with the AntennaSmith by Time Wave. (http://timewave.com). A picture of this unit appears
below.
Figure 1 AntennaSmith by Time Wave
This device not only measures SWR and other characteristics of an antenna system but also
provides plots of this data over specified ranges. Two types of these plots appear below.
SWR plot on AntennaSmith
Smithchart plot on AntennaSmith
Figure 2 On-screen plots viewed on the AntennaSmith
Software accompanying the unit provides for the upload of data and plots to a PC. Where
possible, direct measurements have been taken of these antenna systems and these direct
measurements appear next to predicted values from our modeling.
6
ANTENNAS FOR 100 POUND DXPEDITIONS
5 REFERENCE ANTENNAS
Before we begin investigating the performance of antennas we might use on a 100 Pound
DXpedition we should look at the performance of some standard antenna designs. (Note that
these standard antenna designs may also make fine antennas for our purposes!) This will
give us a baseline from which we might compare antennas. The two antenna types to be
discussed are a
•
Quarter wave vertical antenna – This is a ground mounted antenna fed about 29
inches above ground with 16 radials.
•
Vertical dipole antenna – This is an antenna that does not require a radial system, is
center fed, and can be deployed in even small areas.
An antenna of each type is modeled for all five bands 10, 12, 15, 17, and 20 meters. We
begin with the quarter-wave vertical.
5.1
Quarter-wave verticals
The following antennas are modeled with simple runs of AWG 16 wire. Antennas serving
bands 10-20 meters such antennas can be easily constructed with a simple fishing pole
holding up the vertical element and radials tied to trees or stakes. Though presented here as a
“reference” antenna, these antennas could be used on a 100 Pound DXpedition. The space
required to fully deploy the antennas is greater than what we typically expect to have, but if
the space is available these antennas are fine choices giving good value for weight, size, and
performance.
I have used a “fishing pole vertical” for 40 meters (which is also good on 15 meters) and 80
meters on several trips with only two elevated radials with very good results. Since 20-foot
fishing poles are available from major sporting good outlets for very little money, these
antennas are also a very cost effective way to get on the air in that remote location.
The following reference antennas are shown with 16 radials. Even four radials provide a
surprisingly good antenna. The reader is encouraged to model these antennas for themselves.
In the mean time, we spend the next few sections discussing these simple antennas for 10
through 20 meter bands.
5.1.1 10 meter Quarter-wave Vertical with Radials
A full-sized quarter-wave vertical with radials is one of the simplest antennas to make or
model. This example is a 10m vertical antenna with 16 radials. The antenna is fed, and its
radials emanate from, a height of 29 inches. This puts the top of the antenna about 12 feet
off the ground, easily held by a modestly sized collapsible fishing pole. A Black Widow
pole 13 foot in length (with a closed length of 45.5 inches) is less than $11, for example.
Longer poles up to 20 feet cost under $20. Such poles would make fine masts to hold up the
upper-end of one of these quarter wave verticals.
The model image for this antenna appears below.
7
ANTENNAS FOR 100 POUND DXPEDITIONS
Figure 3 Full-sized 10m quarter-wave vertical
This is a pretty good antenna and it is very simple. The EZNEC model description for it
follows.
EZNEC+ ver. 5.0
Quarter-wave vertical for 10m
8/31/2007
10:46:00 AM
--------------- ANTENNA DESCRIPTION --------------Frequency = 28.3 MHz
Wire Loss: Copper -- Resistivity = 1.74E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Insulation
Conn.
1
W2E1
Coord. (in)
X
Y
0,
0,
Z
29
Conn.
Coord. (in)
X
Y
0,
0,
0,
Dia (in)
Z
132
Segs
Diel C
#16
6
Thk(in)
1
0
2
W3E1
0,
0,
29
103,
29
#16
6
1
0
3
W4E1
0,
0,
29
-39.416,95.1596,
29
#16
6
1
0
4
W5E1
0,
0,
29
-72.832, 72.832,
29
#16
6
1
0
5
W6E1
0,
0,
29
-95.16,39.4164,
29
#16
6
1
0
6
W7E1
0,
0,
29
0,
29
#16
6
1
0
7
W8E1
0,
0,
29
-95.16,-39.416,
29
#16
6
1
0
8
W9E1
0,
0,
29
-72.832,-72.832,
29
#16
6
1
0
9
W10E1
0,
0,
29
-39.416, -95.16,
29
#16
6
1
0
10
W11E1
0,
0,
29
-103,
29
#16
6
1
0
11
W12E1
0,
0,
29
39.4164, -95.16,
29
#16
6
1
0
12
W13E1
0,
0,
29
72.832,-72.832,
29
#16
6
1
0
13
W14E1
0,
0,
29
95.1596,-39.416,
29
#16
6
1
0
14
W15E1
0,
0,
29
0,
29
#16
6
1
0
15
W16E1
0,
0,
29
95.1596,39.4165,
29
#16
6
1
0
16
W17E1
0,
0,
29
72.832, 72.832,
29
#16
6
1
0
17
W1E1
0,
0,
29
39.4164,95.1596,
29
#16
6
1
0
Total Segments: 102
8
End 2
-103,
0,
103,
ANTENNAS FOR 100 POUND DXPEDITIONS
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
% From E1
1
Actual Pos.
% From E1
0.00
8.33
Amplitude
Seg
(V/A)
1
Phase
Type
(deg.)
1
0
I
No loads specified
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
This model yields the following SWR plot. (All SWR plots for antennas in this white paper
are for antennas operated over “good” ground.)
Figure 4 SWR for quarter wave vertical on 12m
The plots for this antenna over good ground appear below.
9
ANTENNAS FOR 100 POUND DXPEDITIONS
10m quarter-wave vertical
10m quarter-wave vertical
Figure 5 Quarter wave vertical on 10m over good ground
The plots for the same antenna over poor ground appear below.
10m quarter-wave vertical
10m quarter-wave vertical
Figure 6 Quarter wave vertical on 10m over poor ground
This pattern of plots is repeated throughout this white paper. A diagram or photograph of the
antenna system discussed is presented. Modeling information along with SWR plots come
next. Then, far-field plots showing the antenna performance over both a good ground and
over a poor ground are shown. This presentation provides an excellent overview of the
10
ANTENNAS FOR 100 POUND DXPEDITIONS
antenna and its performance. The modeling input data additionally provides a means for the
reader to perform these calculations themselves and possibly further alter the simulated
environment to learn more.
The ARRL Antenna Book is an excellent resource for anything relating to amateur radio
antennas. It is also recommended that the reader study the relevant sections of that reference
work for any particular antenna type discussed here (vertical monopole, vertical dipole,
etc.). Such reading will help set reasonable expectations for each antenna type. For example,
this antenna presents about 30 ohms of R, not 50 ohms. This is expected in a vertical
monopole with a good radial system.
The far-field plots have a great deal of information within them. The general shape of the
azimuth plot shows the relative strength of the signals emitted in any given direction. These
relative strengths are normalized to the 0 dB outer ring and directions where the signal is
less than the maximum appear plotted within the circle intersecting with graphed rings of -5
dB, -10 dB, etc.
The elevation plot provides an indication of the angles where most of the radiation is being
emitted. This simple vertical monopole has only one lobe but other antennas may have
several lobes and deep nulls between them. Those deep nulls would indicate angles where
little or no radiation is emitted. The large lobes would represent the antenna’s “take off
angle”, the angle from which the most radiation is emitted or received.
Though the relative shapes of the plots for good ground and poor ground may appear
similar, the magnitude of the radiation represented by the outer ring may be vastly different.
In this case, the outer ring for the good ground plot represents 0.33 dBi; the outer ring for
the poor ground plot represents -0.2 dBi. In other antenna systems the effects of ground on
antenna efficiency are more pronounced.
Finally, the effects of ground can also affect the antenna’s take off angle. Generally, better
ground lowers the take off angle. This is a problem for two reasons: (1) some of the more
interesting and fun places to visit have sandy soil and provide a very poor ground, and (2)
these interesting places are typically far away from stations we would like to work so a low
take off angle is especially important. There is a discussion about the effects of ground, and
things that might be done to manage it, later in the paper.
This system of diagrams for SWR and far-field plots provides some visual means of
comparing antenna systems to a standard set of antennas and to each other. A significant
amount of space is dedicated to these comparisons later in this paper.
11
ANTENNAS FOR 100 POUND DXPEDITIONS
5.1.2 12 meter Quarter-wave Vertical with Radials
This example is a 12m vertical antenna with 16 radials. Like the 10m vertical described
above, this one is also mounted with the feed point 29 inches above ground.
Figure 7 Full-sized 12m quarter-wave vertical
The model description data is shown below.
EZNEC+ ver. 5.0
Fishing pole vertical for 12m
8/31/2007
10:30:18 AM
--------------- ANTENNA DESCRIPTION -------------Frequency = 24.9 MHz
Wire Loss: Copper -- Resistivity = 1.74E-08 ohm-m, Rel. Perm. = 1
---- WIRES --------------No.
End 1
Conn.
12
Coord. (in)
X
Y
End 2
Z
Conn.
Coord. (in)
X
Y
-----------
Dia (in)
Z
Segs
Diel C
Ins
Thk(in)
1
W2E1
0,
0,
29
0,
0,
145
1
6
1
0
2
W3E1
0,
0,
29
0,
141,
29
#16
6
1
0
3
W4E1
0,
0,
29
-53.958,130.267,
29
#16
6
1
0
4
W5E1
0,
0,
29
-99.702,99.7021,
29
#16
6
1
0
5
W6E1
0,
0,
29
-130.27,53.9583,
29
#16
6
1
0
6
W7E1
0,
0,
29
0,
29
#16
6
1
0
7
W8E1
0,
0,
29
-130.27,-53.958,
29
#16
6
1
0
8
W9E1
0,
0,
29
-99.702,-99.702,
29
#16
6
1
0
9
W10E1
0,
0,
29
-53.958,-130.27,
29
#16
6
1
0
10
W11E1
0,
0,
29
-141,
29
#16
6
1
0
11
W12E1
0,
0,
29
53.9584,-130.27,
29
#16
6
1
0
12
W13E1
0,
0,
29
99.702,-99.702,
29
#16
6
1
0
13
W14E1
0,
0,
29
130.267,-53.958,
29
#16
6
1
0
14
W15E1
0,
0,
29
0,
29
#16
6
1
0
15
W16E1
0,
0,
29
130.267,53.9584,
29
#16
6
1
0
16
W17E1
0,
0,
29
99.7021, 99.702,
29
#16
6
1
0
-141,
0,
141,
ANTENNAS FOR 100 POUND DXPEDITIONS
17
W1E1
0,
0,
29
53.9583,130.267,
29
#16
6
1
0
Total Segments: 102
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
% From E1
1
Actual Pos.
% From E1
0.00
8.33
Amplitude
Seg
(V/A)
1
Phase
Type
(deg.)
1
0
I
No loads specified
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
This yields an SWR curve as shown below.
Figure 8 SWR for quarter wave vertical on 12m
The plots for this antenna over good ground appear below.
13
ANTENNAS FOR 100 POUND DXPEDITIONS
12m quarter-wave vertical
12m quarter-wave vertical
Figure 9 Quarter wave vertical on 12m over good ground
The plots for the same antenna over poor ground appear below.
12m quarter-wave vertical
12m quarter-wave vertical
Figure 10 Quarter wave vertical on 12m over poor ground
14
ANTENNAS FOR 100 POUND DXPEDITIONS
5.1.3 15 meter Quarter-wave Vertical with Radials
This example is a 15m vertical antenna with 16 radials at 29 inches. The model view of this
antenna appears below.
Figure 11 Full-sized 15m quarter-wave vertical
The model data for this antenna is shown below.
EZNEC+ ver. 5.0
Quarter wave vertical for 15m
8/31/2007
11:26:14 AM
--------------- ANTENNA DESCRIPTION --------------Frequency = 21.2 MHz
Wire Loss: Copper -- Resistivity = 1.74E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
Coord. (in)
Z
End 2
Conn.
Coord. (in)
Dia (in)
Segs
X
Y
X
Y
1
W2E1
0,
0,
29
0,
0,
167
#16
6
1
0
2
W3E1
0,
0,
29
0,
134,
29
#16
6
1
0
3
W4E1
0,
0,
29
-51.28,
123.8,
29
#16
6
1
0
4
W5E1
0,
0,
29
-94.752,94.7524,
29
#16
6
1
0
5
W6E1
0,
0,
29
-123.8,51.2795,
29
#16
6
1
0
6
W7E1
0,
0,
29
0,
29
#16
6
1
0
7
W8E1
0,
0,
29
-123.8, -51.28,
29
#16
6
1
0
8
W9E1
0,
0,
29
-94.752,-94.752,
29
#16
6
1
0
9
W10E1
0,
0,
29
-51.28, -123.8,
29
#16
6
1
0
10
W11E1
0,
0,
29
-134,
29
#16
6
1
0
11
W12E1
0,
0,
29
51.2796, -123.8,
29
#16
6
1
0
12
W13E1
0,
0,
29
94.7523,-94.752,
29
#16
6
1
0
13
W14E1
0,
0,
29
123.8, -51.28,
29
#16
6
1
0
14
W15E1
0,
0,
29
0,
29
#16
6
1
0
15
W16E1
0,
0,
29
123.8,51.2797,
29
#16
6
1
0
-134,
0,
134,
Z
Ins
Diel C
Thk(in)
15
ANTENNAS FOR 100 POUND DXPEDITIONS
16
W17E1
0,
0,
29
94.7524,94.7523,
29
#16
6
1
0
17
W1E1
0,
0,
29
51.2795,
29
#16
6
1
0
123.8,
Total Segments: 102
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
% From E1
1
Actual Pos.
% From E1
0.00
8.33
Amplitude
Seg
(V/A)
1
1
Phase
Type
(deg.)
0
I
No loads specified
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
This antenna yields the following SWR plot.
Figure 12 SWR for quarter wave vertical on 15m
16
ANTENNAS FOR 100 POUND DXPEDITIONS
15m quarter-wave vertical
15m quarter-wave vertical
Figure 13 Quarter wave vertical on 15m over good ground
The plots for the same antenna over poor ground appear below.
15m quarter-wave vertical
15m quarter-wave vertical
Figure 14 Quarter wave vertical on 15m over poor ground
17
ANTENNAS FOR 100 POUND DXPEDITIONS
5.1.4 17 meter Quarter-wave Vertical with Radials
This example is a 17m vertical antenna with 16 radials at 29 inches. The model view for this
antenna appears below.
Figure 15 Full-sized 17m quarter-wave vertical
The model data for this antenna appears below.
EZNEC+ ver. 5.0
Quarter wave vertical for 17m
8/31/2007
2:02:43 PM
--------------- ANTENNA DESCRIPTION -------------Frequency = 18.1 MHz
Wire Loss: Copper -- Resistivity = 1.74E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
18
Coord. (in)
Z
End 2
Conn. X
Coord. (in)
Z
Insu
X
Y
1
W2E1
0,
0,
29
0,
0,
191
#16
6
1
0
2
W3E1
0,
0,
29
0,
158,
29
#16
6
1
0
3
W4E1
0,
0,
29
-60.464,145.973,
29
#16
6
1
0
4
W5E1
0,
0,
29
-111.72,111.723,
29
#16
6
1
0
5
W6E1
0,
0,
29
-145.97,60.4639,
29
#16
6
1
0
6
W7E1
0,
0,
29
0,
29
#16
6
1
0
7
W8E1
0,
0,
29
-145.97,-60.464,
29
#16
6
1
0
8
W9E1
0,
0,
29
-111.72,-111.72,
29
#16
6
1
0
9
W10E1
0,
0,
29
-60.464,-145.97,
10
W11E1
0,
0,
29
11
W12E1
0,
0,
12
W13E1
0,
13
W14E1
0,
-158,
Y
Dia (in) Segs
Diel C
Thk(in)
29
#16
6
1
0
-158,
29
#16
6
1
0
29
60.464,-145.97,
29
#16
6
1
0
0,
29
111.723,-111.72,
29
#16
6
1
0
0,
29
145.973,-60.464,
29
#16
6
1
0
0,
ANTENNAS FOR 100 POUND DXPEDITIONS
14
W15E1
0,
0,
29
15
W16E1
0,
0,
16
W17E1
0,
17
W1E1
0,
158,
0,
29
#16
6
1
0
29
145.973,60.4641,
29
#16
6
1
0
0,
29
111.723,111.723,
29
#16
6
1
0
0,
29
60.4639,145.973,
29
#16
6
1
0
Total Segments: 102
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
% From E1
1
Actual Pos.
% From E1
0.00
8.33
Amplitude
Seg
(V/A)
1
1
Phase
Type
(deg.)
0
I
No loads specified
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.001
3
Height
R Coord.
(in)
(in)
0
0
This model yields an SWR plot as follows.
Figure 16 SWR for quarter wave vertical on 17m
The far-field plot for this antenna over good ground appears below.
19
ANTENNAS FOR 100 POUND DXPEDITIONS
17m quarter-wave vertical
17m quarter-wave vertical
Figure 17 Quarter wave vertical on 17m over good ground
The far-field plot for this antenna over poor ground appears below.
17m quarter-wave vertical
17m quarter-wave vertical
Figure 18 Quarter wave vertical on 17m over poor ground
20
ANTENNAS FOR 100 POUND DXPEDITIONS
5.1.5 20 meter Quarter-wave Vertical with Radials
This example is a 17m vertical antenna with 16 radials at 29 inches. The model view of this
antenna appears below.
Figure 19 Full-sized 20m quarter-wave vertical
The model data for this antenna is found below.
EZNEC+ ver. 5.0
Quarter wave vertical for 17m
8/31/2007
2:27:48 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 14.1 MHz
Wire Loss: Copper -- Resistivity = 1.74E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
Coord. (in)
X
Y
Z
End 2
Conn.
Coord. (in
X
Y
Dia (in)
Z
Segs
Ins
Diel C
Thk(in)
1
W2E1
0,
0,
29
0,
0,
235
#16
6
1
0
2
W3E1
0,
0,
29
0,
201,
29
#16
6
1
0
3
W4E1
0,
0,
29
-76.919,
185.7,
29
#16
6
1
0
4
W5E1
0,
0,
29
-142.13,142.129,
29
#16
6
1
0
5
W6E1
0,
0,
29
-185.7,76.9193,
29
#16
6
1
0
6
W7E1
0,
0,
29
0,
29
#16
6
1
0
7
W8E1
0,
0,
29
-185.7,-76.919,
29
#16
6
1
0
8
W9E1
0,
0,
29
-142.13,-142.13,
29
#16
6
1
0
9
W10E1
0,
0,
29
-76.919, -185.7,
29
#16
6
1
0
10
W11E1
0,
0,
29
-201,
29
#16
6
1
0
11
W12E1
0,
0,
29
76.9194, -185.7,
29
#16
6
1
0
12
W13E1
0,
0,
29
142.128,-142.13,
29
#16
6
1
0
13
W14E1
0,
0,
29
185.7,-76.919,
29
#16
6
1
0
-201,
0,
21
ANTENNAS FOR 100 POUND DXPEDITIONS
14
W15E1
0,
0,
29
15
W16E1
0,
0,
16
W17E1
0,
17
W1E1
0,
201,
0,
29
#16
6
1
0
29
185.7,76.9195,
29
#16
6
1
0
0,
29
142.129,142.128,
29
#16
6
1
0
0,
29
76.9193,
29
#16
6
1
0
Phase
Type
185.7,
Total Segments: 102
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
% From E1
1
Actual Pos.
% From E1
0.00
8.33
Amplitude
Seg
(V/A)
1
1
(deg.)
0
I
No loads specified
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
This model yields the following SWR plot.
Figure 20 SWR for quarter wave vertical on 20m
The far-field plot for this antenna over good ground appears below.
22
ANTENNAS FOR 100 POUND DXPEDITIONS
20m quarter-wave vertical
20m quarter-wave vertical
Figure 21 Quarter wave vertical on 20m over good ground
The far-field plot for this antenna over poor ground appears below.
20m quarter-wave vertical
20m quarter-wave vertical
Figure 22 Quarter wave vertical on 20m over poor ground
23
ANTENNAS FOR 100 POUND DXPEDITIONS
5.2
Half-wave vertical dipoles
Half-wave vertical dipole antennas are what the name describes: a dipole turned on its side
so it is oriented vertically. A full-sized vertical dipole also makes a good basis for
subsequent comparisons. This antenna has the advantage of having a smaller footprint than a
vertical monopole antenna because it does not require radials. However, it is twice as tall as
the quarter-wave antenna and the feed line must be routed away from the antenna carefully
to avoid parasitic coupling.
Half-wave vertical dipoles were used with very good results by the Microlite Penguin
DXpedition team on South Sandwich Island and other places. In addition to being a good
radiator, pairs of vertical dipoles can work together to provide gain in one direction or
another. Visualize a Yagi turned on its side to get the idea. A passive element can be placed
as either a reflector or director for the driven element. If the passive unit is equipped with a
switch to change the length of the elements then the switched vertical dipole antenna
(SVDA) can be aimed one of two directions, depending on the state of the switch. Since this
passive element could be constructed with a fishing pole and lightweight wire, it is an easy
“throw in” for a 100 Pound DXpedition.
The following sections provide models for full-size half-wave vertical dipole antennas.
Comparing the results of these antennas to the quarter-wave verticals shows that the vertical
dipoles have slightly more gain, a slightly lower take-off angle, and are somewhat more
immune to the effects of ground.
5.2.1 Full-sized 10 Meter Vertical Dipole
Here is a view of the full-sized vertical dipole for 10 meters. A model view of this antenna
appears below. For these antenna models the bottom of the vertical dipole is at 29 inches
with the feed point much higher.
Figure 23 View of the full-sized 10 meter vertical dipole
The EZNEC model description for the full-sized 10m vertical dipole appears below:
EZNEC+ ver. 5.0
Full-size 10m vertical dipole
8/28/2007
11:42:06 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 28.3 MHz
24
ANTENNAS FOR 100 POUND DXPEDITIONS
Wire Loss: Copper -- Resistivity = 1.74E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
Insulation
Conn.
1
End 1
Coord. (in)
X
Y
0,
0,
Z
End 2
Conn.
29
Coord. (in)
X
Y
0,
0,
Dia (in)
Z
Segs
Diel C
225
1
11
1
Thk(in)
0
Total Segments: 11
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
1
Actual Pos.
% From E1
% From E1
50.00
50.00
Amplitude
Seg
(V/A)
6
1
Phase
Type
(deg.)
0
I
No loads specified
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
This model produces the following SWR plot.
Figure 24 SWR for half wave vertical dipole on 10m
25
ANTENNAS FOR 100 POUND DXPEDITIONS
The far-field plot for this antenna appears below. Note that the elevation plot shows a much
lower take off angle for the vertical dipole when compared to that of the vertical monopole.
The outer ring represents 0.76 dBi in these plots. The monopole had an outer ring value of
0.33 dBi. Elevating the feed point and radiator lowered the take-off angle and increased gain
slightly.
Half-wave vertical dipole on 10m
Half-wave vertical dipole on 10m
Figure 25 Half-wave vertical dipole on 10m over good ground
Below are the plots for poor ground. Note that the outer ring represents 0.61 dBi in these plots
over poorer ground, 0.1 dB down from the good ground plot, but far less of a degradation than
that observed when we moved a quarter wave monopole from good ground to poor ground.
Except for a slight reduction in overall gain, the antenna performed about as well over poor
ground as it did over good ground. This is most likely due to getting the feed point of the antenna
well away from the lossy ground.
Half wave vertical dipole (HWVD) antennas are a fine choice for 100 Pound DXpeditions
because they are relatively easy to erect, have a small footprint, and are relatively immune to the
poor sandy ground of islands and beaches (places attractive for our lightweight DXpeditions). A
40m antenna is unwieldy at 66 to 70 feet, but antennas for bands 10-15m are very practical, light,
and easy to deploy.
26
ANTENNAS FOR 100 POUND DXPEDITIONS
Half-wave vertical dipole on 10m
Half-wave vertical dipole on 10m
Figure 26 Half-wave vertical dipole on 10m over poor ground
5.2.2 Full-sized 12 Meter Vertical Dipole
Here is a view of the full-sized vertical dipole for 12 meters with its base at 29 inches.
Figure 27 View of the full-sized 12 meter vertical dipole
The EZNEC model description for the full-sized 12m vertical dipole appears below.
EZNEC+ ver. 5.0
Full-size 12m vertical dipole
8/31/2007
2:59:43 PM
--------------- ANTENNA DESCRIPTION -------------Frequency = 24.9 MHz
Wire Loss: Copper -- Resistivity = 1.74E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
X
Coord. (in)
Y
End 2
Z
Conn.
X
Coord. (in) Dia (in)
Y
Z
Segs
Insulation
Diel C
Thk(in)
27
ANTENNAS FOR 100 POUND DXPEDITIONS
1
0,
0,
29
0,
0,
256
1
11
1
Total Segments: 11
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
1
Actual Pos.
% From E1
% From E1
50.00
50.00
Amplitude
Seg
(V/A)
6
1
Phase
Type
(deg.)
0
I
No loads specified
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
This model yields the following SWR plot.
Figure 28 SWR for half wave vertical dipole on 12m
28
0
ANTENNAS FOR 100 POUND DXPEDITIONS
Half-wave vertical dipole on 12m
Half-wave vertical dipole on 12m
Figure 29 Half-wave vertical dipole on 12m over good ground
The far-field plot for this antenna over poor ground appears below.
Half-wave vertical dipole on 12m
Half-wave vertical dipole on 12m
Figure 30 Half-wave vertical dipole on 12m over poor ground
29
ANTENNAS FOR 100 POUND DXPEDITIONS
5.2.3 Full-sized 15 Meter Vertical Dipole
Here is a view of the full-sized vertical dipole for 15 meters with the base at 29 inches.
Figure 31 View of the full-sized 15 meter vertical dipole
The EZNEC model description for the full-sized 15m vertical dipole appears below:
EZNEC+ ver. 5.0
Full-size 15m vertical dipole
8/31/2007
3:22:12 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 21.2 MHz
Wire Loss: Copper -- Resistivity = 1.74E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
1
Coord. (in)
X
Y
0,
0,
End 2
Z
Conn.
29
Coord. (in)
X
Y
0,
0,
Dia (in)
Segs
Z
295
1
11
Total Segments: 11
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
1
Actual Pos.
% From E1
% From E1
50.00
50.00
Amplitude
Seg
(V/A)
6
1
No loads specified
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
This model yields the following SWR plot.
30
Ins
Diel C
Phase
Type
(deg.)
0
I
1
Thk(in)
0
ANTENNAS FOR 100 POUND DXPEDITIONS
Figure 32 SWR for half wave vertical dipole on 15m
The far-field plot for this antenna over good ground appears below.
31
ANTENNAS FOR 100 POUND DXPEDITIONS
Half-wave vertical dipole on 15m
Half-wave vertical dipole on 15m
Figure 33 Half-wave vertical dipole on 15m over good ground
The far field plot for this antenna over poor ground appears below.
Half-wave vertical dipole on 15m
Half-wave vertical dipole on 15m
Figure 34 Half-wave vertical dipole on 15m over poor ground
32
ANTENNAS FOR 100 POUND DXPEDITIONS
5.2.4 Full-sized 17 Meter Vertical Dipole
Here is a view of the full-sized vertical dipole for 17 meters with the base at 29 inches.
Figure 35 View of the full-sized 17 meter vertical dipole
The EZNEC model description for the full-sized 17m vertical dipole appears below.
EZNEC+ ver. 5.0
Full-size 17m vertical dipole
8/31/2007
3:37:12 PM
-------------- ANTENNA DESCRIPTION --------------Frequency = 18.1 MHz
Wire Loss: Copper -- Resistivity = 1.74E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
1
Coord. (in)
X
Y
0,
0,
End 2
Z
Conn.
29
Coord. (in)
X
Y
0,
0,
Dia (in)
Segs
Z
Ins
Diel C
341
1
11
1
Thk(in)
0
Total Segments: 11
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
1
Actual Pos.
% From E1
% From E1
50.00
50.00
Amplitude
Seg
(V/A)
6
1
Phase
Type
(deg.)
0
I
No loads specified
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
This model yields the following SWR plot.
33
ANTENNAS FOR 100 POUND DXPEDITIONS
Figure 36 SWR for half wave vertical dipole on 17m
The far-field plot for this antenna over good ground appears below.
34
ANTENNAS FOR 100 POUND DXPEDITIONS
Half-wave vertical dipole on 17m
Half-wave vertical dipole on 17m
Figure 37 Half-wave vertical dipole on 17m over good ground
The far-field plot for this antenna over poor ground appears below.
Half-wave vertical dipole on 17m
Half-wave vertical dipole on 17m
Figure 38 Half-wave vertical dipole on 17m over poor ground
35
ANTENNAS FOR 100 POUND DXPEDITIONS
5.2.5 Full-sized 20 Meter Vertical Dipole
Here is a view of the full-sized vertical dipole for 20 meters with the base at 29 inches.
Figure 39 View of the full-sized 20 meter vertical dipole
The EZNEC model description for the full-sized 20m vertical dipole appears below:
EZNEC+ ver. 5.0
Full-size 20m vertical dipole
8/31/2007
3:45:25 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 14.1 MHz
Wire Loss: Copper -- Resistivity = 1.74E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
1
Coord. (in)
X
Y
0,
End 2
Z
0,
Conn.
29
Coord. (in)
X
Y
0,
0,
Dia (in)
Segs
Z
Diel C
430
1
11
Total Segments: 11
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
1
Actual Pos.
% From E1
% From E1
50.00
50.00
Amplitude
Seg
(V/A)
6
1
No loads specified
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
This model yields an SWR plot as follows.
36
Ins
Phase
Type
(deg.)
0
I
1
Thk(in)
0
ANTENNAS FOR 100 POUND DXPEDITIONS
Figure 40 SWR for half wave vertical dipole on 20m
The far-field plot for this antenna over good ground appears below.
37
ANTENNAS FOR 100 POUND DXPEDITIONS
Half-wave vertical dipole on 20m
Half-wave vertical dipole on 20m
Figure 41 Half-wave vertical dipole on 20m over good ground
The far-field plot for this antenna over poor ground appears below.
Half-wave vertical dipole on 20m
Half-wave vertical dipole on 20m
Figure 42 Half-wave vertical dipole on 20m over poor ground
38
ANTENNAS FOR 100 POUND DXPEDITIONS
6 FORCE-12 SIGMA-5 ANTENNA
The Force-12 Sigma-5 antenna is a five-band antenna. The antenna will be treated as five
different antennas for our discussion starting with the antenna on 10 meters. I have used this
antenna on brief stints on Georges Island (NA-148) in Boston Harbor, among other places,
and have found it to be surprisingly good for its size.
The phrase “surprisingly good for its size” is suspect, of course. Rather than provide vague
assurances that this device is not a dummy load direct mathematical comparisons will be
made between this antenna and others. Those results should sway the reader to also say
“surprisingly good for its size.”
The other aspect of our analysis is subjective. This unit weighs about eight pounds and
requires a single piece of coax for the five bands it services. Assuming the weight of RG-8X
is about 2 pounds for a 50 foot length, we can service five bands with a single 2 pound run
instead of feeding 5 different antennas with a total of 10 pounds of coax. Not only is the
antenna reasonably light, but the multiple bands also saved 8 pounds of coax from our
weight budget! Is that worth a dB? Is that worth 1.5 dBs? These are questions to be asked
when planning every trip.
The drawbacks of the Force-12 Sigma-5 are two: though it does break down into sections
about 2 feet in length, the center section with its controller is bulky and difficult to pack
easily. Additionally, the coils within the controller, especially the 20-meter coils, need to be
adjusted after travel as they are not rigid and can change shape when jostled. Still, if you can
find a way to pack it and do not mind doing a quick adjustment once you reach your
destination, this is an interesting antenna design.
6.1
Force-12 Sigma-5 on 10 meters
The Force-12 Sigma-5 is a shortened half-wave vertical antenna with a matching box that
allows operations on five bands: 10, 12,15,17, and 20 meters. The antenna breaks down into
roughly 2-foot pieces and stands about 9 feet tall when assembled.
39
ANTENNAS FOR 100 POUND DXPEDITIONS
Figure 43 The assembled Force-12 Sigma-5
The basic structure of the antenna is that of a vertical dipole with capacity hats on both ends.
The 21st edition of the ARRL Antenna Book describes this design as a Compact Vertical
Dipole though that text was for a single-band design. The multi-band design of the Sigma-5
begins with a full-sized 10m antenna and adds loading coils to provide a match on the other
bands. Relays controlled by a remote switch engage these coils as needed. The coils, relays,
and matching system are housed in a plastic enclosure at the center of the antenna. The
figure below shows the circuit board and coils for this unit.
40
ANTENNAS FOR 100 POUND DXPEDITIONS
Figure 44 Force-12 Sigma-5 matching circuit
The feed line and control cable come in from the top of the picture. Ferrite surrounds those
lines to help reduce common-mode currents. The circuit board has coils on the top-side
(shown) and relays on the bottom (not shown). The control cable is used to energize relays
and select the coils to be used for loading the antenna.
Starting from the center of the circuit board and moving out we find:
•
The matching stub / coil – This coil is copper in color and provides a matching stub
for the antenna.
•
The 12m matching coil – On either side of the matching stub are two widely spaced
coils used to load the antenna on 12 meters.
•
The 15m matching coil – The tightly wound coils after the 12m coils are used to
load the antenna for 15 meters. Note that the 15-meter band is selected by including
both the 12m coil and 15m coils.
•
The 17m matching coil – The next set of coils are for 17 meters. This band is
matched with the 12m, 15m, and 17m coils in series.
•
The 20m matching coil – The coils found nearest the ends of the circuit board are
for 20 meters. All four coils (12m, 15m, 17m, and 20m) are in series to provide a
match on this band.
If no relays are energized then all coils are active and the antenna can be used on 20 meters.
Other bands are selected by energizing particular relays that bypass one or more coils. The
41
ANTENNAS FOR 100 POUND DXPEDITIONS
modeling description section describes how the lengths of aluminum and coils are measured
and placed within the model.
6.1.1 Model description
There are three things that need to be specified for this model: the dimensions of the
aluminum structure for the antenna, the values and placement of the coils and matching stub,
and the type of ground beneath the antenna. Each of these will be addressed in turn.
The antenna consists of two sizes of aluminum tubing: 1 inch and 0.5 inch stock. The
vertical element is one inch in diameter; the arms of the capacity hat are 0.5 inches. The
modeling software was having trouble with the connections of the half-inch arms to the one
inch vertical section so I made a small alteration in the description. Both ends of the tall
vertical radiator are now only a half-inch in diameter matching the arms. The impact on the
computations should be minimal and this made the modeling program happy.
Arms are 0.5 inches in diameter
Main length is 1.0 inches in diame
ter
Last 6 inches are 0.5 inches in diameter
Figure 45 Force-12 Sigma-5 element diameters
The modeling program also assumes that the driven element is one continuous wire with the
feed point connected to a particular segment. The actual antenna has two separate pieces of
aluminum for the top and bottom elements with some separation between them. I have
combined those two aluminum elements into one for the model. Further, the feed point was
specified to be “50% from end 1” but the actual position selected by the program is slightly
off from that (due to the requirement that the feed point be placed at a segment junction).
The model is made of wires and loads. (Wires can be thin wires or big aluminum tubes.)
This model has seven wires: four arms of the upper and lower capacity hat, and three
42
ANTENNAS FOR 100 POUND DXPEDITIONS
elements in the vertical section, two six inch pieces at the top and bottom, and the main one
inch diameter tube. The assembled antenna is 103 inches high with the lower arms 29 inches
off the ground when mounted on the insulated post packaged with the antenna. Each of the
arms are 24 inches in length. There is a small amount of one inch tubing along the vertical
axis at both the top and bottom of the antenna that is ignored in the model. These
dimensions are sufficient to produce a wire list for our model.
The coils of the model require slightly more work to fully characterize. Using a ruler, I
measured the diameter, length, and number of turns for each of the coils in the unit. With
this information an approximation can be made of the inductance of the coil using the
following formula:
d2 n2
L(H) =
18 d + 40 l
where L(H) is the inductance of the coil, d is the diameter of the coil in inches, n is the
number of turns in the coil, and l is the length of the coil in inches.
The large capacity hats on both ends of the dipole will generate a large capacitive reactance
in-line with the other resistances presented at the feed point of the antenna. To counteract
this excess capacitance, an inductor across the feed point providing an equal and opposite
reactance will be necessary. This is a stub. The stub for this antenna was measured and
calculated as per the table below:
Name
Diameter
Number of turns
Length
XL
Stub
1.5
4
1
0.53 H
This matching stub is present for all bands, not just the 10 meter band.
If the model were a prefect then the antenna would be a good match on 10 meters with just
this in place. For whatever reason, we need to add just a bit of inductance to load each side
of the dipole to make this happen. (This is likely due to the fact that there are traces on the
circuit board and routing around and through relays that have added some small amount of
inductance to our system.) A loading coil with an inductive value of 0.3 H was added to
the model to bring the SWR into a reasonable range. With this extra inductance we get the
following model description of the antenna for EZNEC.
EZNEC+ ver. 5.0
Force-12 Sigma-5 ~ 10m config
8/28/2007
7:47:17 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 28.3 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
Insulation
Conn.
End 1
X
Coord. (in)
Y
Z
End 2
Conn.
X
Coord. (in)
Y
Z
Dia (in)
Segs
Diel C
Thk(in)
43
ANTENNAS FOR 100 POUND DXPEDITIONS
1
W4E1
0,
0,
29
W2E1
0,
0,
35
0.5
6
1
0
2
W1E2
0,
0,
35
W3E1
0,
0,
126
1
22
1
0
3
W2E2
0,
0,
126
W6E1
0,
0,
132
0.5
6
1
0
4
W5E1
0,
0,
29
0,
-24,
29
0.5
6
1
0
5
W1E1
0,
0,
29
0,
24,
29
0.5
6
1
0
6
W7E1
0,
0,
132
0,
-24,
132
0.5
6
1
0
7
W3E2
0,
0,
132
0,
24,
132
0.5
6
1
0
Total Segments: 58
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
2
Actual Pos.
% From E1
% From E1
50.00
52.27
Amplitude
Seg
(V/A)
12
Phase
Type
(deg.)
1
0
I
-------------- LOADS (RLC Type) -------------No.
Specified Pos.
Wire #
Actual Pos.
% From E1
% From E1
Seg
R
L
(ohms)
(uH)
C
(pF)
R Freq
Type
(MHz)
1
2
47.00
47.73
11
Open
0.3
Open
28.3
Par
2
2
55.00
56.82
13
Open
0.3
Open
28.3
Par
3
2
50.00
52.27
12
Short
0.52
Short
0
Ser
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
This description results in the antenna view shown in Figure 46 EZNEC antenna view of
Sigma-5.
44
ANTENNAS FOR 100 POUND DXPEDITIONS
Figure 46 EZNEC antenna view of Sigma-5
6.1.2 Analysis
The antenna model now provides a nice match over the entire 10-meter band as shown in the
figure below.
SWR predicted by model
SWR measured by AntennaSmith
Figure 47 SWR for Force-12 Sigma-5 on 10 meters
The SWR curves above were produced by the EZNEC modeling program (left) and the
AntennaSmith antenna analyzer (right). The 2:1 SWR line in the AntennaSmith plot is the
red vertical line on the left size of the plot. The green area of the plot is the SWR for
frequencies as measured during the sweep of the band. The shape of the measured plot
differs from the shape of the predicted plot, but both plots show the antenna to have SWR
45
ANTENNAS FOR 100 POUND DXPEDITIONS
under 1.5:1 for the bulk of the band and the differences can be attributed to the effects of
ground, the antenna coupling to nearby objects, or the effects of the coax run between the
analyzer and the antenna. The far field plots over good ground give us some idea of the gain
(dBi) and take-off angle of the antenna. These plots appear below.
Force-12 Sigma-5 on 10m
Force-12 Sigma-5 on 10m
Figure 48 Force-12 Sigma-5 on 10m over good ground
Unfortunately, some of the more interesting places we might visit are sandy with very poor
ground. The plots below illustrate those same plots over poor ground.
Force-12 Sigma-5 on 10m
Force-12 Sigma-5 on 10m
Figure 49 Force-12 Sigma-5 on 10m over poor ground
46
ANTENNAS FOR 100 POUND DXPEDITIONS
Two items from these plots give us an idea of what the poorer ground has done to our signal. The
overall gain has gone down slightly and the take-off angle has gone up. Compare these results
with the quarter-wave vertical and full-sized vertical dipole described earlier. The next few plots
are over poor ground.
10m quarter wave
Full-sized vertical dipole
Figure 50 EL 10m quarter wave and vertical dipole over poor ground
The gain for the full-sized vertical dipole is about 0.61 dBi. The gain for the Force-12
Sigma-5 over the same ground is -0.45 dBi. That is a difference of about 1 dB or a factor of
1.25. The difference between the quarter-wave vertical and the Force-12 Sigma-5 is less
than half a dB.
The take-off angle for the full-sized vertical dipole remains low even over poor ground. The
take-off angle for both the quarter-wave vertical and the Force-12 Sigma-5 is about 25
degrees (five degrees higher than the full-sized vertical dipole). So, the smaller Force-12
Sigma-5 compares favorably with the quarter-wave vertical and is only a few degrees higher
than the full-sized vertical dipole on this band.
Returning to the criteria for lightweight DXpeditioning, we are seeking antennas that are
light, easy to set up, easy to break down, and that have a small footprint and low visual
profile. The Force-12 Sigma-5 is much easier to assemble and erect than either of the other
two antennas and is much smaller. For 10 meters, the Force-12 Sigma-5 is a very good
antenna for our purposes.
6.2
Force-12 Sigma-5 matching coil calculations
Each of the bands for the Force-12 Sigma-5 are matched by adding some inductive loading.
(There is no inductive loading for 10-meters in the actual antenna but my model requires a
little. This is evidence that the model does not precisely describe the product.)
Measurements of the various loading coil diameters, number of turns, and coil lengths are
47
ANTENNAS FOR 100 POUND DXPEDITIONS
shown in the table below. The values for the calculated inductive loads are shown along
with the actual inductive loads used in the model (which are slightly higher).
Measured in antenna
Name
Guess
Diameter Number of Length
turns
Determined by
modeling
XL
Total XL
Actual XL
10m
-
-
-
-
-
0.30
12m
1.0
4
1.3
0.22
0.22
0.65
15m
1.0
4
0.5
0.42
0.64
1.21
17m
1.0
5
0.65
0.58
1.22
1.92
20m
1.5
7
1.4
1.43
2.65
3.45 + 2 pF
Table 1 Force-12 Sigma-5 loading coil values
The values in the “Determined by modeling” column are used in subsequent calculations in
the next sections.
6.3
Force-12 Sigma-5 on 12 meters
The physical dimensions of the Force-12 Sigma-5 antenna do not change when changing
bands. The next few sections will therefore concentrate on the performance of the antenna
only and not review other aspects. Further, only the “loads” portion of the antenna model
will be shown as all other elements of the model are identical to the 10-meter version
(except starting frequency).
The loading discussed in the previous section was used to produce load elements as per the
description below.
-------------- LOADS (RLC Type) -------------No.
Specified Pos.
Wire #
Actual Pos.
Seg
R
C
R Freq
Type
% From E1
% From E1
(ohms)
(uH)
(pF)
(MHz)
1
2
47.00
47.73
11
Open
0.65
Open
24.9
Par
2
2
55.00
56.82
13
Open
0.65
Open
24.9
Par
3
2
50.00
52.27
12
Short
0.52
Short
0
Ser
These values give us the following SWR plot:
48
L
ANTENNAS FOR 100 POUND DXPEDITIONS
SWR predicted by model
SWR measured by AntennaSmith
Figure 51 SWR for Force-12 Sigma-5 on 12 meters
The plots for the 10-meter band selection on this antenna showed that the Force-12 Sigma-5
performed relatively well when compared to both a quarter-wave vertical with radials and a fullsized half-wave dipole. The plots for the 12-meter band selection show that moving to this new
band did not sacrifice anything.
49
ANTENNAS FOR 100 POUND DXPEDITIONS
Force-12 Sigma-5 on 12m
Force-12 Sigma-5 on 12m
Figure 52 Force-12 Sigma-5 on 12m over good ground
There was a small reduction in gain over poor ground but the take-off angle remained at 25
degrees as shown in the plots below.
Force-12 Sigma-5 on 12m
Force-12 Sigma-5 on 12m
Figure 53 Force-12 Sigma-5 on 12m over poor ground
The Force-12 Sigma-5 was a good antenna on 10m and remains a good antenna when
switched to 12m compared to a quarter-wave radiator.
50
ANTENNAS FOR 100 POUND DXPEDITIONS
6.4
Force-12 Sigma-5 on 15 meters
The match on 15 meters is under 2:1 for the entire band with the dip just before the center of
the band. We must remember that these numbers are for the model of the antenna (but the
model’s predictions have been verified by direct measurement).
-------------- LOADS (RLC Type) -------------No.
Specified Pos.
Wire #
Actual Pos.
% From E1
% From E1
Seg
L
C
(ohms)
R
(uH)
(pF)
R Freq
(MHz)
Type
1
2
47.00
47.73
11
Open
1.21
Open
21.2
Par
2
2
55.00
56.82
13
Open
1.21
Open
21.2
Par
3
2
50.00
52.27
12
Short
0.52
Short
0
Ser
SWR predicted by model
SWR measured by AntennaSmith
Figure 54 SWR for Force-12 Sigma-5 on 15 meters
Though this antenna is relatively short for a 15 meter antenna the resistance presented is still
relatively high. Assuming all this resistance is not losses, why would the radiation resistance
be so high? Consider the surface area of a 16 AWG wire. The diameter of this wire is about
0.05 inches. The circumference is therefore just under 0.16 inches (0.05 * pi). The
circumference of the one inch aluminum pipe is 3.14 inches. That is nearly 20 times the
surface area of the wire! That is much more metal to radiate.
51
ANTENNAS FOR 100 POUND DXPEDITIONS
The far field plots show the gain even lower than that of the 12m antenna (-0.33 versus 0.04). But, the antenna has lost less than a half a dB from the 10m configuration (-33 versus
+0.44). The take-off angle has remained steady at 25 degrees as shown in the plots below.
Force-12 Sigma-5 on 15m
Force-12 Sigma-5 on 15m
Figure 55 Force-12 Sigma-5 on 15m over good ground
Moving the antenna over poor ground erodes the gain by nearly a dB (-0.33 versus -1.2) as
shown in the plots below.
Force-12 Sigma-5 on 15m
Force-12 Sigma-5 on 15m
Figure 56 Force-12 Sigma-5 on 15m over poor ground
52
ANTENNAS FOR 100 POUND DXPEDITIONS
6.5
Force-12 Sigma-5 on 17 meters
As we move down in frequency the dimensions of the antenna become smaller when
compared to the size of a full-wave. The bottom two bands (17m & 20m) require
significantly more loading that the others. The loading for 17 meters is shown below.
-------------- LOADS (RLC Type) -------------No.
Specified Pos.
Wire #
Actual Pos.
% From E1
% From E1
Seg
L
C
(ohms)
R
(uH)
(pF)
R Freq
(MHz)
Type
1
2
47.00
47.73
11
Open
1.92
Open
18.1
Par
2
2
55.00
56.82
13
Open
1.92
Open
18.1
Par
3
2
50.00
52.27
12
Short
0.52
Short
0
Ser
This provides a nearly flat SWR curve over the whole 100 KHz of the band.
SWR predicted by model
SWR measured by AntennaSmith
Figure 57 SWR for Force-12 Sigma-5 on 17 meters
The far-field plot for the Sigma-5 over good ground on 17m appears below.
53
ANTENNAS FOR 100 POUND DXPEDITIONS
Force-12 Sigma-5 on 17m
Force-12 Sigma-5 on 17m
Figure 58 Force-12 Sigma-5 on 17m over good ground
This is the same antenna configuration over poor ground. Again, the effect of a lossy ground
in the near field degrades gain by nearly a dB.
Force-12 Sigma-5 on 17m
Force-12 Sigma-5 on 17m
Figure 59 Force-12 Sigma-5 on 17m over poor ground
6.6
Force-12 Sigma-5 on 20 meters
Twenty meters is the lowest band for the Force-12 Sigma-5. The loading for this band is
shown below.
54
ANTENNAS FOR 100 POUND DXPEDITIONS
-------------- LOADS (RLC Type) -------------No.
Specified Pos.
Wire #
Actual Pos.
Seg
R
L
C
R Freq
Type
% From E1
% From E1
(ohms)
(uH)
(pF)
1
2
47.00
47.73
11
Open
3.45
2
(MHz)
14.1
Par
2
2
55.00
56.82
13
Open
3.45
2
14.1
Par
3
2
50.00
52.27
12
Short
0.52
Short
0
Ser
This loading provides a 2:1 match over about 200 KHz of the band. The manual for the
antenna provides instructions on how to adjust the coil to change the center frequency of the
antenna for this band. Spreading the coils slightly changes the inter-winding capacitance of
the coil. In fact, it was necessary to add a small capacitance (2 pF) to the model to show this
nice SWR plot.
Measurement not taken
SWR predicted by model
SWR measured by AntennaSmith
Figure 60 SWR for Force-12 Sigma-5 on 20 meters
The far-field plots for this antenna on 20m over good ground follows.
55
ANTENNAS FOR 100 POUND DXPEDITIONS
Force-12 Sigma-5 on 20m
Force-12 Sigma-5 on 20m
Figure 61 Force-12 Sigma-5 on 20m over good ground
Below is a far-field plot for this antenna on 20m over poor ground.
Force-12 Sigma-5 on 20m
Force-12 Sigma-5 on 20m
Figure 62 Force-12 Sigma-5 on 20m over poor ground
56
ANTENNAS FOR 100 POUND DXPEDITIONS
7 TW ANTENNAS TW2010 TRAVELER
The TW Antennas TW2010 Traveler antenna is similar in design to the Force-12 Sigma-5.
The notable differences are in the height of the antenna (the Traveler is shorter), the length
of the arms (the traveler has longer arms), the diameter of the elements (the Traveler uses
one inch aluminum tubing for all elements), and the control mechanism (the Traveler has a
electronics control package that can perform automatic band switching when connected to a
radio).
Both antennas use loading coils and relays to select the combination of coils in use. Both
antennas sit relatively low to the ground and depend on the large capacity hats to provide
good efficiencies and matches on the five supported bands.
The TW Antennas TW2010 Traveler is a relatively new antenna as of this writing. The
analysis below shows that it is competitive with the Force-12 Sigma-5 with performance
down 0.7 to 1.5 dB from the Force-12 offering. The take-off angle of the Traveler also rises
about 5 degrees from the Force-12. Still, the TW Antennas Traveler packs and travels better
than the Force-12 Sigma-5, and deployment is easier than the Sigma-5 with no tools (and no
bolts) assembly.
The next few sections will discuss the TW Antennas TW2010 Traveler antenna. As with the
Force-12 Sigma-5, the various bands will be treated as different antennas though they all use
the same physical structure. Band changes indicate a change in the loading coils; band
changes do not require any other physical changes to the antenna.
7.1
TW Antennas TW2010 Traveler on 10 meters
The TW Antennas Traveler model is nearly identical to the Force-12 Sigma-5 with just a
few things changed. Like the Force-12 Sigma-5, the TW Antennas Traveler has a matching
stub (coil) to counteract the large capacitance from the arms. The details of this stub follows.
Name
Diameter
Number of turns
Length
XL
Stub
0.65
4
1
0.37 H
The methodology for determining this value is described in the next section. Here are the
model details for the TW Traveler antenna including the loading information for 10 meters.
EZNEC+ ver. 5.0
TW Antennas Traveler
8/29/2007
3:54:19 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 28.3 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
Coord. (in)
X
Y
End 2
Z
1
W2E1
0,
0,
20
2
W3E1
0,
0,
20
Conn.
W4E1
Coord. (in)
Dia (in)
Segs
Diel C
Ins
X
Y
Z
Thk(in)
0,
0,
100
1
30
1
0
0,
-30,
20
1
11
1
0
57
ANTENNAS FOR 100 POUND DXPEDITIONS
3
W1E1
0,
0,
20
0,
30,
20
1
11
1
0
4
W5E1
0,
0,
100
0,
-30,
100
1
11
1
0
5
W1E2
0,
0,
100
0,
30,
100
1
11
1
0
Total Segments: 74
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
1
Actual Pos.
% From E1
% From E1
50.00
51.67
Amplitude
Seg
Phase
(V/A)
16
Type
(deg.)
1
0
I
-------------- LOADS (RLC Type) ------------No.
Specified Pos.
Wire #
Actual Pos.
% From E1
% From E1
R
Seg
(ohms)
L
(uH)
C
R Freq
(pF)
(MHz)
Type
1
1
48.00
48.33
15
Open
0.28
0
28.3
Par
2
1
54.00
55.00
17
Open
0.28
0
28.3
Par
3
1
50.00
51.67
16
Short
0.37
Short
0
Ser
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
This model provides the following view of the antenna.
Figure 63 TW Antennas Traveler model view
As with the Force-12 Sigma-5, we shall present the 10 meter data here and then show only
the different loading for the other bands serviced by this antenna.
58
ANTENNAS FOR 100 POUND DXPEDITIONS
The stub and loading coil values provide the following SWR on the 10-meter band.
Figure 64 SWR for TW Antennas Traveler on 10m
The far field plots for this antenna on 10-meters over good ground appears below
TW Antennas Traveler on 10m
TW Antennas Traveler on 10m
Figure 65 TW Antennas Traveler on 10m over good ground
The far-field plot for this antenna on 10m over poor ground appears below.
59
ANTENNAS FOR 100 POUND DXPEDITIONS
TW Antennas Traveler on 10m
TW Antennas Traveler on 10m
Figure 66 TW Antennas Traveler on 10m over poor ground
Comparisons to the performance of the Force-12 Sigma-5 can now be made. Below are a
sequence of figures with the Sigma-5 plot on the left and Traveler on the right.
Force-12 Sigma-5
TW Antennas Traveler
Figure 67 AZ Sigma-5 and Traveler on 10m over good ground
60
ANTENNAS FOR 100 POUND DXPEDITIONS
Force-12 Sigma-5
TW Antennas Traveler
Figure 68 EL Sigma-5 and Traveler on 10m over good ground
Force-12 Sigma-5
TW Antennas Traveler
Figure 69 AZ Sigma-5 and Traveler on 10m over poor ground
61
ANTENNAS FOR 100 POUND DXPEDITIONS
Force-12 Sigma-5
TW Antennas Traveler
Figure 70 EL Sigma-5 and Traveler on 10m over poor ground
7.2
TW Antennas TW2010 Traveler matching coil calculations
Measuring the coils is straightforward if you have the hardware in front of you. But, how do
you measure things if you don’t? What if you don’t own the device? As I did not own this
antenna when the analysis was first done, this was the first problem to overcome. (I have
since purchased the antenna.) The solution was to measure from a photograph instead of
from the coils themselves. Adobe Photoshop provides all the tools you need. The techniques
shown here should be useful for any challenge of this type. Here is how I did it.
I took a photograph of the match-box that was featured in the TW Antennas brochure. This
was a PDF so much of the detail remained when the page was enlarged. Once I had a view
with sufficient detail, I captured that portion of the brochure into a file and opened
Photoshop.
Once the image was opened with Photoshop it was just a matter of scaling the picture so the
aluminum pipe was measured to be one inch in the Photoshop ruler system. All other
distances could be approximated using the Photoshop measuring tool. A figure below
illustrates this.
62
ANTENNAS FOR 100 POUND DXPEDITIONS
Figure 71 Measuring Traveler coils with Photoshop
The measurements and final inductances after experimental modeling appear below. As you
can see, these values were about as close as those measured directly on the Force-12 Sigma5. And, all this was from just a picture!
Measured in antenna
Guess
Determined by
modeling
Name
Diameter
Number of
turns
Length
XL
Total XL
Actual XL
10m
0.85
2
0.2
0.12
0.12
0.28
12m
0.65
3
0.3
0.16
0.28
0.58
15m
0.75
4
0.3
0.35
0.64
1.10
17m
0.75
5
0.52
0.41
1.05
1.75
20m
0.7
8
0.83
0.68
1.73
3.25 + 1 pF
Table 2 TW Antenna Traveler coil values
63
ANTENNAS FOR 100 POUND DXPEDITIONS
7.3
TW Antennas Traveler on 12 meters
The model data for the TW Antennas Traveler antenna on 12 meters is the same as the 10meter model except for the loading. Those details are found below.
-------------- LOADS (RLC Type) ------------No.
Specified Pos.
Wire #
% From E1
Actual Pos.
% From E1
Seg
R
(ohms)
L
C
(uH)
(pF)
R Freq
(MHz)
1
1
48.00
48.33
15
Open
0.58
0
24.9
Par
2
1
54.00
55.00
17
Open
0.58
0
24.9
Par
3
1
50.00
51.67
16
Short
0.37
Short
0
Ser
Figure 72 SWR for TW Antennas Traveler on 12m
The far-field plots for this antenna on 12m over good ground appear below.
64
Type
ANTENNAS FOR 100 POUND DXPEDITIONS
TW Antennas Traveler on 12m
TW Antennas Traveler on 12m
Figure 73 TW Antennas Traveler on 12m over good ground
The far-field plots for this antenna on 12m over poor ground appear below.
TW Antennas Traveler on 12m
TW Antennas Traveler on 12m
Figure 74 TW Antennas Traveler on 12m over poor ground
Again, we compare the two very similar antenna designs of the Force-12 Sigma-5 and the TW
Antennas TW2010 with side-by-side far-field plots over good ground and poor ground.
65
ANTENNAS FOR 100 POUND DXPEDITIONS
Force-12 Sigma-5
TW Antennas Traveler
Figure 75 AZ Sigma-5 and Traveler on 12m over good ground
Force-12 Sigma-5
TW Antennas Traveler
Figure 76 EL Sigma-5 and Traveler on 12m over good ground
66
ANTENNAS FOR 100 POUND DXPEDITIONS
Force-12 Sigma-5
TW Antennas Traveler
Figure 77 AZ Sigma-5 and Traveler on 12m over poor ground
Force-12 Sigma-5
TW Antennas Traveler
Figure 78 EL Sigma-5 and Traveler on 12m over poor ground
67
ANTENNAS FOR 100 POUND DXPEDITIONS
7.4
TW Antennas Traveler on 15 meters
The model data for the TW Antennas Traveler antenna on 15 meters is the same as the 10meter model except for the loading. Those details are found below.
-------------- LOADS (RLC Type) ------------No.
Specified Pos.
Wire #
% From E1
Actual Pos.
% From E1
Seg
R
(ohms)
L
(uH)
C
R Freq
(pF)
(MHz)
1
1
48.00
48.33
15
Open
1.1
0
21.2
Par
2
1
54.00
55.00
17
Open
1.1
0
21.2
Par
3
1
50.00
51.67
16
Short
0.37
Short
0
Ser
Figure 79 SWR for TW Antennas Traveler on 15m
The far-field plots for this antenna on 15m over good ground appears below.
68
Type
ANTENNAS FOR 100 POUND DXPEDITIONS
TW Antennas Traveler
TW Antennas Traveler
Figure 80 TW Antennas Traveler over good ground
The far-field plot for this antenna on 15m over poor ground appears below.
TW Antennas Traveler
TW Antennas Traveler
Figure 81 TW Antennas Traveler on 15m over poor ground
Direct comparisons using far-field plots for the Sigma-5 and TW2010 are shown below.
69
ANTENNAS FOR 100 POUND DXPEDITIONS
Force-12 Sigma-5
TW Antennas Traveler
Figure 82 AZ Sigma-5 and Traveler on 15m over good ground
Force-12 Sigma-5
TW Antennas Traveler
Figure 83 EL Sigma-5 and Traveler on 15m over good ground
70
ANTENNAS FOR 100 POUND DXPEDITIONS
Force-12 Sigma-5
TW Antennas Traveler
Figure 84 AZ Sigma-5 and Traveler on 15m over poor ground
Force-12 Sigma-5
TW Antennas Traveler
Figure 85 AZ Sigma-5 and Traveler on 15m over poor ground
7.5
TW Antennas Traveler on 17 meters
The model data for the TW Antennas Traveler antenna on 17 meters is the same as the 10meter model except for the loading. Those details are found below.
-------------- LOADS (RLC Type) -------------
71
ANTENNAS FOR 100 POUND DXPEDITIONS
No.
Specified Pos.
Wire #
Actual Pos.
% From E1
% From E1
Seg
R
L
(ohms)
(uH)
C
R Freq
(pF)
(MHz)
1
1
48.00
48.33
15
Open
1.75
0
18.1
Par
2
1
54.00
55.00
17
Open
1.75
0
18.1
Par
3
1
50.00
51.67
16
Short
0.37
0
Ser
Short
Figure 86 SWR for TW Antennas Traveler on 17m
The far-field plots for this antenna on 17m over good ground appears below.
72
Type
ANTENNAS FOR 100 POUND DXPEDITIONS
TW Antennas Traveler
TW Antennas Traveler
Figure 87 TW Antennas Traveler on 17m over good ground
The far-field plot for this antenna on 17m over poor ground appears below.
TW Antennas Traveler
TW Antennas Traveler
Figure 88 TW Antennas Traveler on 17m over poor ground
Comparisons between the Sigma-5 and TW2010 are shown with far-field plots over both
good and poor ground below.
73
ANTENNAS FOR 100 POUND DXPEDITIONS
Force-12 Sigma-5
TW Antennas Traveler
Figure 89 AZ Sigma-5 and Traveler on 17m over good ground
Force-12 Sigma-5
TW Antennas Traveler
Figure 90 EL Sigma-5 and Traveler on 17m over good ground
74
ANTENNAS FOR 100 POUND DXPEDITIONS
Force-12 Sigma-5
TW Antennas Traveler
Figure 91 AZ Sigma-5 and Traveler on 17m over poor ground
Force-12 Sigma-5
TW Antennas Traveler
Figure 92 EL Sigma-5 and Traveler on 17m over poor ground
7.6
TW Antennas Traveler on 20 meters
The model data for the TW Antennas Traveler antenna on 20 meters is the same as the 10meter model except for the loading. Those details are found below.
-------------- LOADS (RLC Type) --------------
75
ANTENNAS FOR 100 POUND DXPEDITIONS
No.
Specified Pos.
Wire #
Actual Pos.
Seg
R
L
C
Freq
% From E1
% From E1
(ohms)
(uH)
(pF)
(MHz)
1
1
48.00
48.33
15
Open
3.25
1
14.2
Par
2
1
54.00
55.00
17
Open
3.25
1
14.2
Par
3
1
50.00
51.67
16
Short
0.37
Short
0
Ser
Figure 93 SWR for TW Antennas Traveler on 20m
The far field plot for this antenna on 20m over good ground appears below.
76
Type
ANTENNAS FOR 100 POUND DXPEDITIONS
TW Antennas Traveler
TW Antennas Traveler
Figure 94 TW Antennas Traveler on 20m over good ground
The far-field plot for this antenna on 20m over poor ground appears below.
TW Antennas Traveler
TW Antennas Traveler
Figure 95 TW Antennas Traveler on 20m over poor ground
77
ANTENNAS FOR 100 POUND DXPEDITIONS
Comparisons of the Sigma-5 and TW2010 on 20m over both good and poor ground are
made with far-field plots below.
Force-12 Sigma-5
TW Antennas Traveler
Figure 96 AZ Sigma-5 and Traveler on 20m over good ground
Force-12 Sigma-5
TW Antennas Traveler
Figure 97 EL Sigma-5 and Traveler on 20m over good ground
78
ANTENNAS FOR 100 POUND DXPEDITIONS
Force-12 Sigma-5
TW Antennas Traveler
Figure 98 AZ Sigma-5 and Traveler on 20m over poor ground
Force-12 Sigma-5
TW Antennas Traveler
Figure 99 EL Sigma-5 and Traveler on 20m over poor ground
79
ANTENNAS FOR 100 POUND DXPEDITIONS
8 STANDARD BUDDIPOLE
The Buddipole Antennas Buddipole (just “Buddipole” henceforth) is really an antenna
component system that allows for the construction and deployment of many different
antenna configurations depending on the requirements. The standard package can be used to
build antennas covering 2-40 meters. Larger coils are available that provide for the
construction of 80 meter antennas. There is no Buddipole antenna to evaluate; there are
many, many Buddipole configurations to evaluate. This white paper will attempt to evaluate
some small subset of these options.
There are several components that are used to construct these antenna configurations. Some
of these are:
•
22 inch antenna arm – This is an aluminum tube 0.75 inches in diameter and 21.5
inches in length (plus threading on one end).
•
Black coil – The Buddipole system comes with two coils: a Black coil and a Red
coil. Dimensions and corresponding inductances for popular tap-points are given in a
table below.
•
Red coil – Similar to the Black coil.
•
5.5 foot whips – There are several styles of whips available in differing lengths,
colors, and construction. The standard Buddipole package uses stainless steel 5.5
foot whips.
•
VersaTee – This is the feed point for the antenna and the place where elements are
affixed. There is a threaded hole in the bottom of this block to accept the standard
Buddipole mast. Three threaded mounts appear on the left, right, and top of the
VersaTee to accept antenna arms or whips.
There are many other accessories but the first models will consist of only these items.
One of the important things about this system is that it packs small and travels well. The
long bag holds the system and the 16 foot mast; the small bag holds the system and the 8
foot mast. Pictures of the packed systems appear below.
80
ANTENNAS FOR 100 POUND DXPEDITIONS
Long Buddipole in bag
Small Buddipole system in the bag
Figure 100Buddipole in the bag
The two coils Black and Red are 1.5 inches in diameter and have 12 turns per inch.
Default settings call for specific taps and whip lengths. Those taps are shown below
along with the associated inductance.
BLACK
Tap
2
4
6
14
19
36
Diameter
1.5
1.5
1.5
1.5
1.5
1.5
length
0.17
0.33
0.50
1.17
1.58
3.00
X(L)
0.27
0.89
1.72
5.99
8.99
19.84
RED
Tap
2
4
10
23
40
Diameter
1.5
1.5
1.5
1.5
1.5
length
0.17
0.33
0.83
1.92
3.33
X(L)
0.27
0.89
3.73
11.48
22.45
Black
Blue
No
Red
Green
Blue
No
Construction of the basic dipole configuration can be achieved by following a simple
recipe of assembling the antenna and selecting the appropriate coil taps and whip
lengths. After assembly, fine tuning can be done by adding or subtracting a little whip
length from one side or the other.
The act of “tapping” a coil is done by inserting a small hook into the coil windings.
There is a threaded head on the top of this hook and a plastic knob screwed into the
thread. To tap a coil just loosen the plastic knob on the top of the hook, thread the hook
81
ANTENNAS FOR 100 POUND DXPEDITIONS
through the appropriate coil winding, and then tighten the knob until the hook is snug
against the wire. A five-inch wander lead is attached to each coil. This wander lead is
inserted into the top of the hook to complete the connection. Tapping a coil typically
takes only a few seconds.
Note that the five-inch wander lead must be included in the length of one of the wires for
our model. I have added those five inches to the length of the whips so each specified
whip length is augmented by five inches for each design.
The recommended recipes for Buddipole dipole configurations appears below.
BASIC DIPOLE TUNING
RED SIDE
BLACK SIDE
BANDS
Coils
Total whip
sections out
Tap
Coils
Total whip
sections out
Tap
40 meters
YES
5.5
NO
YES
5
NO
30 meters
YES
6
23
YES
6
19
20 meters
YES
6
GREEN 10
YES
6
BLUE 14
17 meters
YES
4.5
GREEN 10
YES
6
BLACK 6
15 meters
YES
6
RED 4
YES
6
BLACK 6
12 meters
YES
6
2
YES
6
4
10 meters
YES
5
2
YES
6
2
6 meters
Whips only (no coils, no arms) – 4.5 sections out each side
2 meters
Whips only (no coils, no arms) 1 section + 2 inches (15” total) each side
Table 3 Recipes for Buddipole dipole configurations
These recipes are good starting points for tuning the Buddipole but the effects of ground,
proximity of nearby objects, or even particular band segment to be match will demand
variants. The two most obvious variations are obtained by either lengthening or shortening a
whip or by tapping a different coil turn.
As of this writing the Buddipole “Deluxe Package” configuration was $399 and consisted of
the following:
82
•
The Buddipole Antenna (9 bands, 2 - 40 meters) with 25 foot coax assembly
(includes VersaTee)
•
Tripod - extendable legs and locking base
•
Portable Mast – extends to 8’ in height
ANTENNAS FOR 100 POUND DXPEDITIONS
•
Rotating Arm Kit – change configurations
•
Antenna System Bag – padded Cordura nylon w/shoulder strap
•
Extra Stainless Steel Telescopic Whip
•
3 Coil Clips
•
Antenna Operating Manual
•
A 10-page modeling report
Substituting a 16 foot mast and longer bag brings the total system cost to $454 (as of this
writing). One additional part will also be included in the analysis. The Triple Ratio Switched
Balun (TRSB) is a device that can be placed at the feed point that provides good isolation of
the feed line from the antenna and a switched transformer that can match 50:50 ohms (1:1),
50:25 ohms (2:1), or 50:12.5 ohms (4:1) to accommodate antenna configurations with very
low impedances. The TRSB is $79 bringing the total of the evaluated system to $533.
This white paper will consider the following configurations that can be constructed with the
standard Buddipole kit (plus extra parts as described above).
•
Dipole
•
An “L” with a vertical “hot side” and horizontal “cold side”
•
A vertical with sloping radial
The configurations will appear at differing mast heights to show the affect of mast height on
performance. We begin with the humble dipole.
8.1
Buddipole Horizontal Dipole
The standard Buddipole masts are either 8 feet or 16 feet in length. A dipole at 16 feet for
any band but 10 meters is a very, very low dipole. Modeling confirms that a low-hung
horizontal dipole does not yield good results for DX work.
8.1.1 Buddipole Horizontal Dipole for 10-meters at 8 feet
This is one of the most simple configurations for the Buddipole. The VersaTee has two
horizontal elements. One side has (starting from the center) one 22-inch arm, the Black coil,
and one six foot whip. The other side has one 22-inch arm, the Red coil, and one six foot
whip. Both coils are tapped at the second turn.
Here is the model file for this antenna:
EZNEC+ ver. 5.0
Buddipole dipole 10m @ 8 ft
8/29/2007
10:38:43 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 28.3 MHz
Wire Loss: Aluminum (6061-T6) – Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
X
Coord. (in)
Y
End 2
Z
Conn.
X
Coord. (in)
Y
Dia (in)
Z
Segs
Ins
Diel C
Thk(in)
83
ANTENNAS FOR 100 POUND DXPEDITIONS
1
W2E2
2
3
W1E2
0,
-22,
96
W3E1
0,
22,
96
0.75
11
1
0
0,
-93,
96
W1E1
0,
-22,
96
0.5
11
1
0
0,
22,
96
0,
82.5,
96
0.5
11
1
0
C
R Freq
Type
(MHz)
Total Segments: 33
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
1
Actual Pos.
% From E1
% From E1
50.00
50.00
Amplitude
Seg
Phase
(V/A)
6
Type
(deg.)
1
0
I
-------------- LOADS (RLC Type) -------------No.
Specified Pos.
Wire #
% From E1
Actual Pos.
% From E1
1
1
0.00
4.55
2
1
100.00
95.45
R
Seg
L
(ohms)
(uH)
(pF)
1
Short
0.27
Short
28.3
Ser
11
Short
0.27
Short
28.3
Ser
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.001
5
Height
R Coord.
(in)
(in)
0
0
This model gives us the following antenna view in EZNEC:
Figure 101 Buddipole on 10m at 8 feet
This is a very low dipole even for 10 meters. The far field plots confirm that the take-off
angle for this antenna is very high. The plot for this antenna on 10m over good ground
appears below.
84
ANTENNAS FOR 100 POUND DXPEDITIONS
Buddipole 10m horizontal dipole at 8 feet
Buddipole 10m horizontal dipole at 8 feet
Figure 102 Buddipole horizontal dipole for 10m at 8 feet over good ground
The far-field plot for the antenna over poor ground appears below.
Buddipole 10m horizontal dipole at 8 feet
Buddipole 10m horizontal dipole at 8 feet
Figure 103 Buddipole horizontal dipole for 10m at 8 feet over poor ground
85
ANTENNAS FOR 100 POUND DXPEDITIONS
No other HF dipole configurations will be modeled for the 8-foot mast as the pattern can
only get worse for bands below 10 meters. Instead, all subsequent dipole analysis will be
done on the 16-foot mast.
8.1.2 Buddipole Horizontal Dipole for 10-meters at 16 feet
The Buddipole system has two standard mast lengths: 8 foot and 16 foot. Below is an
alalysis for the 10-meter configuration raised to 16 feet. The SWR plot did not change much
and the bulk of the 10 meter band is better than 2:1. The only thing that changed in these
two models is the Z component of the three wires. Here is the model for this antenna.
EZNEC+ ver. 5.0
Buddipole dipole 10m @ 8 ft
8/29/2007
10:38:43 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 28.3 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
1
W2E2
2
3
W1E2
Coord. (in)
X
Y
End 2
Z
0,
-22,
192
0,
-93,
192
0,
22,
192
Conn.
Coord. (in)
X
W3E1
Y
0,
W1E1
Dia (in)
Segs
Z
Ins
Diel C
Thk(in)
22,
192
0.75
11
1
0
0,
-22,
192
0.5
11
1
0
0,
82.5,
192
0.5
11
1
0
Type
Total Segments: 33
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
1
Actual Pos.
% From E1
% From E1
50.00
50.00
Amplitude
Seg
Phase
(V/A)
6
Type
(deg.)
1
0
I
-------------- LOADS (RLC Type) -------------No.
Specified Pos.
Wire #
% From E1
Actual Pos.
% From E1
1
1
0.00
4.55
2
1
100.00
95.45
C
R Freq
(ohms)
R
(uH)
(pF)
(MHz)
1
Short
0.27
Short
28.3
Ser
11
Short
0.27
Short
28.3
Ser
Seg
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.001
5
Height
R Coord.
(in)
(in)
0
0
The SWR plot for this antenna appears below.
86
L
ANTENNAS FOR 100 POUND DXPEDITIONS
SWR predicted by model
SWR measured by AntennaSmith
Figure 104 SWR for Buddipole horizontal dipole for 10m at 16 feet
The far-field plot for the Buddipole dipole configuration for 10-meters over good ground at 16
feet appears below.
87
ANTENNAS FOR 100 POUND DXPEDITIONS
Buddipole 10m horizontal dipole at 16 feet
Buddipole 10m horizontal dipole at 16 feet
Figure 105 Buddipole horizontal dipole for 10m at 16 feet over good ground
The far-field plot for this antenna over poor ground appears below.
Buddipole 10m horizontal dipole at 16 feet
Buddipole 10m horizontal dipole at 16 feet
Figure 106 Buddipole horizontal dipole for 10m at 16 feet over poor ground
This antenna is worthy of comparison to some of the vertical antennas described earlier. One
of the better antennas was the full-sized vertical dipole for 10-meters. We compare that
antenna to this new Buddipole configuration over good ground.
88
ANTENNAS FOR 100 POUND DXPEDITIONS
Half-wave vertical dipole on 10m
Buddipole 10m horizontal dipole at 16 feet
Figure 107 Half-wave vertical dipole vs. Buddipole horizontal dipole for 10 meters
The clear winner here is the Buddipole dipole configuration with nearly 7 dBi of gain versus the
vertical at less than 1 dBi. Assuming the target is broadside to the antenna, you get about an Sunit improvement over the vertical. Even with the take-off angle of the vertical being ten degrees
lower than the Buddipole horizontal dipole, the Buddipole wins.
8.1.3 Buddipole Horizontal Dipole for 12-meters at 16 feet
The Buddipole dipole on 12m at a height of 16 feet appears below. Here is the model for this
antenna.
EZNEC+ ver. 5.0
Buddipole dipole 12m @16 ft
8/30/2007
8:18:05 AM
--------------- ANTENNA DESCRIPTION --------------Frequency = 24.9 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
1
W2E2
2
3
W1E2
Coord. (in)
X
End 2
Conn.
Coord. (in)
X
Y
Dia (in)
Z
Segs
Ins
Y
Z
Diel C
Thk(in)
0,
-22,
192
W3E1
0,
22,
192
0.75
11
1
0
0,
-93,
192
W1E1
0,
-22,
192
0.5
11
1
0
0,
22,
192
0,
93,
192
0.5
11
1
0
Total Segments: 33
-------------- SOURCES -------------No.
Specified Pos.
Actual Pos.
Amplitude
Phase
Type
89
ANTENNAS FOR 100 POUND DXPEDITIONS
Wire #
1
1
% From E1
% From E1
50.00
50.00
Seg
(V/A)
6
(deg.)
1
0
I
-------------- LOADS (RLC Type) -------------No.
Specified Pos.
Wire #
% From E1
Actual Pos.
% From E1
1
1
0.00
4.55
2
1
100.00
95.45
R
L
Seg (ohms)
(uH)
C
R Freq
(pF)
(MHz)
Type
1
Short
0.89
Short
24.9
Ser
11
Short
0.27
Short
24.9
Ser
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
The SWR plot for the Buddipole dipole for 12-meters at 16 feet appears below.
SWR predicted by model
SWR measured by AntennaSmith
Figure 108 SWR for Buddipole horizontal dipole for 12m at 16 feet
The far-field plot for the Buddipole dipole for 12-meters at 16 feet over good ground
appears below.
90
ANTENNAS FOR 100 POUND DXPEDITIONS
Buddipole 12m horizontal dipole at 16 feet
Buddipole 12m horizontal dipole at 16 feet
Figure 109 Buddipole horizontal dipole for 12m at 16 feet over good ground
The Buddipole dipole for 12-meters at 16 feet over poor ground appears below.
Buddipole 12m horizontal dipole at 16 feet
Buddipole 12m horizontal dipole at 16 feet
Figure 110 Buddipole horizontal dipole for 12m at 16 feet over poor ground
91
ANTENNAS FOR 100 POUND DXPEDITIONS
8.1.4 Buddipole Horizontal Dipole for 15-meters at 16 feet
The Buddipole on 15 meters at 16 feet appears below. Here is the model for this antenna.
EZNEC+ ver. 5.0
Buddipole dipole 15m @16 ft
8/30/2007
8:28:37 AM
--------------- ANTENNA DESCRIPTION --------------Frequency = 21.2 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Insulation
Conn.
1
W2E2
2
3
W1E2
Coord. (in)
X
Y
End 2
Z
Coord. (in)
Y
Dia (in)
Segs
Conn.
X
0,
-22,
192
W3E1
0,
22,
192
Z
0.75
11
Diel C
1
0
0,
-93,
192
W1E1
0,
-22,
192
0.5
11
1
0
0,
22,
192
0,
93,
192
0.5
11
1
0
Total Segments: 33
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
1
Actual Pos.
% From E1
% From E1
50.00
50.00
Amplitude
Seg
Phase
(V/A)
6
Type
(deg.)
1
0
I
-------------- LOADS (RLC Type) -------------No.
Specified Pos.
Wire #
% From E1
Actual Pos.
% From E1
1
1
0.00
4.55
2
1
100.00
95.45
R
Seg
(ohms)
1
Short
11
Short
L
C
R Freq
Type
(uH)
(pF)
(MHz)
1.72
Short
21.2
Ser
0.89
Short
21.2
Ser
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
The SWR plot for the Buddipole dipole on 15-meters at 16 feet appears below.
92
Thk(in)
ANTENNAS FOR 100 POUND DXPEDITIONS
SWR predicted by model
SWR measured by AntennaSmith
Figure 111 SWR for Buddipole horizontal dipole for 15m at 16 feet
The predicted SWR curve looks much different than that measured by the AntennaSmith. This
could easily be due to the effects of the particular ground or proximity of other objects in the
near field of the antenna. Again, as with the 10-meter antenna at only 8 feet, this 15-meter
antenna at only 16 feet is very, very low for a dipole as evidenced by the far-field plots below.
The far-field plot for the Buddipole on 15-meters at 16 feet over good ground appears first.
93
ANTENNAS FOR 100 POUND DXPEDITIONS
Buddipole 15m horizontal dipole at 16 feet
Buddipole 15m horizontal dipole at 16 feet
Figure 112 Buddipole horizontal dipole for 15m at 16 feet over good ground
The Buddipole dipole for 15-meters at 16 feet over poor ground appears below.
Buddipole 15m horizontal dipole at 16 feet
Buddipole 15m horizontal dipole at 16 feet
Figure 113 Buddipole horizontal dipole for 15m at 16 feet over poor ground
94
ANTENNAS FOR 100 POUND DXPEDITIONS
8.1.5 Buddipole Horizontal Dipole for 17-meters at 16 feet
The Buddipole on 17-meters at 16 feet appears below. Here is the model data for this
antenna.
EZNEC+ ver. 5.0
Buddipole dipole 17m @16 ft
8/30/2007
10:18:52 AM
--------------- ANTENNA DESCRIPTION --------------Frequency = 18.1 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
1
W2E2
2
3
W1E2
Coord. (in)
X
Y
End 2
Z
Conn.
Coord. (in)
X
Dia (in)
Y
Segs
Z
Ins
Diel CThk(in)
0,
-22,
192
W3E1
0,
22,
192
0.75
11
1
0
0,
-93,
192
W1E1
0,
-22,
192
0.5
11
1
0
0,
22,
192
0,
73,
192
0.5
11
1
0
Total Segments: 33
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
1
Actual Pos.
% From E1
% From E1
50.00
50.00
Amplitude
Seg
Phase
(V/A)
6
Type
(deg.)
1
0
I
-------------- LOADS (RLC Type) --------------
No.
Specified Pos.
Wire #
% From E1
Actual Pos.
% From E1
1
1
0.00
4.55
2
1
100.00
95.45
R
Seg
(ohms)
L
(uH)
C
(pF)
R Freq
Type
(MHz)
1
Open
1.72
1
18.1
Par
11
Open
3.73
1
18.1
Par
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
The dipole has an extremely low resistance. The Buddipole Triple Ratio Switched Balun
(TRSB) provides a switched transformer that matches a 50 ohm feed line to a 25 ohm load,
or a 12.5 ohm load. This configuration presents 25 ohms so the 2:1 setting of the TRSB will
be employed. This yields the SWR graph as shown below.
95
ANTENNAS FOR 100 POUND DXPEDITIONS
Measurement not taken
SWR predicted by model
SWR measured by AntennaSmith
Figure 114 SWR for Buddipole horizontal dipole for 17m at 16 feet
The tuning is very sharp for this antenna. This configuration is impractical for DX operation with
its tedious tuning and high take-off angle.
Note that as sharp as the tuning might be for the 17-meter dipole configuration, it would be even
worse for the 20-meter dipole configuration. Further, the 20-meter antenna at 16 feet would be at
least as bad as the 10-meter antenna at 8 feet. Therefore, the 20-meter antenna will not be
evaluated here.
For illustrate these problems the far-field plot for the 17-meter dipole configuration at 16-feet
over good ground is presented above. Note the extremely high take-off angle.
96
ANTENNAS FOR 100 POUND DXPEDITIONS
Buddipole 17m horizontal dipole at 16 feet
Buddipole 17m horizontal dipole at 16 feet
Figure 115 Buddipole horizontal dipole for 17m at 16 feet over good ground
The Buddipole dipole configuration for 17-meters at 16 feet over poor ground is shown
below.
Buddipole 17m horizontal dipole at 16 feet
Buddipole 17m horizontal dipole at 16 feet
Figure 116 Buddipole horizontal dipole for 17m at 16 feet over poor ground
97
ANTENNAS FOR 100 POUND DXPEDITIONS
8.2
Buddipole Vertical with L-arm radial at 8 feet
The “L” antenna is like the dipole except that the “hot” side of the antenna is mounted on
the top of the VersaTee to make a vertical antenna with one (loaded) radial. I have used this
configuration occasionally but the long and heavy horizontal piece make the antenna
precarious to balance since the center of gravity is so far away from the mast. Also, as can
be seen by the plots below, the pattern from the antenna is a bit bizarre. Perhaps this section
is an exercise in what not to do.
8.2.1 Buddipole Vertical with L-arm radial for 10m at 8 feet
The “L” for 10 meters at 8 feet appears below. Here is the model data for that antenna.
EZNEC+ ver. 5.0
Buddipole vert-L 10m at 8 ft
8/30/2007
11:30:32 AM
--------------- ANTENNA DESCRIPTION --------------Frequency = 28.3 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES -------------No.
End 1
Conn.
Coord. (in)
X
Y
End 2
Z
1
W3E1
0,
0,
192
2
W1E2
0,
0,
214
3
W1E1
0,
0,
192
4
W3E2
0,
22,
192
Coord. (in)
Dia (in)
Segs
Conn.
X
Y
W2E1
0,
0,
214
0.75
11
1
0
0,
0,
280
0.5
11
1
0
0,
22,
192
0.5
11
1
0
0,
93,
192
0.5
11
1
0
W4E1
Z
Ins
Diel C
Thk(in)
Total Segments: 44
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
1
% From E1
Actual Pos.
% From E1
0.00
4.55
Amplitude
Seg
(V/A)
1
Phase
Type
(deg.)
1
0
I
-------------- LOADS (RLC Type) -------------No.
Specified Pos.
Wire #
% From E1
Actual Pos.
% From E1
R
Seg
(ohms)
(uH)
C
(pF)
R Freq
Type
(MHz)
1
1
100.00
95.45
11
Open
0.27
Open
28.3
Par
2
3
100.00
95.45
11
Open
0.27
Open
28.3
Par
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
98
L
0.005
13
Height
R Coord.
(in)
(in)
0
0
ANTENNAS FOR 100 POUND DXPEDITIONS
The TRSB is used to match the antenna at 25 ohms which yields the following SWR curve.
Note that if you wished to match the CW portion of the 10 meter band that the top whip can
be pulled out a few more inches to shift the center frequency down.
Measurement not taken
SWR predicted by model
SWR measured by AntennaSmith
Figure 117 SWR for Buddipole vertical with L-radial on 10m at 8 feet
This antenna is illustrated below.
99
ANTENNAS FOR 100 POUND DXPEDITIONS
Figure 118 Buddipole vertical with L-radial on 10m at 8 feet
The far-field pattern for this antenna over good ground appears below.
Buddipole vertical with L-radial on 10m
Buddipole vertical with L-radial on 10m
Figure 119 Buddipole vertical with L-radial on 10m at 8 feet over good ground
The far-field pattern for this antenna over poor ground appears below.
100
ANTENNAS FOR 100 POUND DXPEDITIONS
Buddipole vertical with L-radial on 10m
Buddipole vertical with L-radial on 10m
Figure 120 Buddipole vertical with L-radial on 10m at 8 feet over poor ground
8.2.2 Buddipole Vertical with L-arm radial for 12m at 8 feet
The “L” for 12 meters appears below.
Figure 121 Buddipole vertical with L-radial on 12m at 8 feet
Here is the model data for this antenna.
EZNEC+ ver. 5.0
Buddipole vert-L 12m at 8 ft
8/30/2007
11:51:05 AM
--------------- ANTENNA DESCRIPTION --------------Frequency = 24.9 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
101
ANTENNAS FOR 100 POUND DXPEDITIONS
--------------- WIRES --------------No.
End 1
Conn.
Coord. (in)
X
Y
End 2
Z
1
W3E1
0,
0,
192
2
W1E2
0,
0,
214
3
W1E1
0,
0,
192
4
W3E2
0,
22,
192
Coord. (in)
Dia (in)
Segs
Conn.
X
Y
W2E1
0,
0,
214
0.75
11
1
0
0,
0,
285
0.5
11
1
0
0,
22,
192
0.5
11
1
0
0,
93,
192
0.5
11
1
0
W4E1
Z
Diel C
Total Segments: 44
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
1
% From E1
Actual Pos.
% From E1
0.00
4.55
Amplitude
Seg
(V/A)
1
Phase
Type
(deg.)
1
0
I
-------------- LOADS (RLC Type) -------------No.
Specified Pos.
Wire #
% From E1
Actual Pos.
% From E1
R
Seg
C
R Freq
(ohms)
(uH)
(pF)
(MHz)
Type
1
100.00
95.45
11
Open
0.89
Open
24.9
Par
2
3
100.00
95.45
11
Open
0.27
Open
24.9
Par
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------Cond.
Diel. Const.
(S/m)
1
102
L
1
No.
0.005
13
Ins
Height
R Coord.
(in)
(in)
0
0
Thk(in)
ANTENNAS FOR 100 POUND DXPEDITIONS
Measurement not taken
SWR predicted by model
SWR measured by AntennaSmith
Figure 122 SWR for Buddipole vertical with L-radial on 12m at 8 feet
Buddipole vertical with L-radial on 12m
Buddipole vertical with L-radial on 12m
Figure 123 Buddipole vertical with L-radial on 12m at 8 feet over good ground
103
ANTENNAS FOR 100 POUND DXPEDITIONS
Buddipole vertical with L-radial on 12m
Buddipole vertical with L-radial on 12m
Figure 124 Buddipole vertical with L-radial on 12m at 8 feet over poor ground
8.2.3 Buddipole Vertical with L-arm radial for 15m at 8 feet
The “L” for 15 meters appears below.
Figure 125 Buddipole vertical with L-radial on 15m at 8 feet
Here is the model data for this antenna.
EZNEC+ ver. 5.0
104
ANTENNAS FOR 100 POUND DXPEDITIONS
Buddipole vert-L 15m at 8 ft
8/30/2007
1:06:51 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 21.2 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
Coord. (in)
X
Y
End 2
Z
1
W3E1
0,
0,
192
2
W1E2
0,
0,
214
3
W1E1
0,
0,
192
4
W3E2
0,
22,
192
Coord. (in)
Dia (in)
Segs
Conn.
X
Y
W2E1
0,
0,
214
0.75
11
1
0
0,
0,
280
0.5
11
1
0
0,
22,
192
0.5
11
1
0
0,
93,
192
0.5
11
1
0
W4E1
Z
Ins
Diel C
Thk(in)
Total Segments: 44
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
1
% From E1
Actual Pos.
% From E1
0.00
4.55
Amplitude
Seg
(V/A)
1
Phase
Type
(deg.)
1
0
I
-------------- LOADS (RLC Type) -------------No.
Specified Pos.
Wire #
% From E1
Actual Pos.
% From E1
R
Seg
L
C
R Freq
(ohms)
(uH)
(pF)
(MHz)
Type
1
1
100.00
95.45
11
Open
1.72
Open
21.2
Par
2
3
100.00
95.45
11
Open
0.89
Open
21.2
Par
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
The SWR plot for this antenna appears below.
105
ANTENNAS FOR 100 POUND DXPEDITIONS
Measurement not taken
SWR predicted by model
SWR measured by AntennaSmith
Figure 126 SWR for Buddipole vertical with L-radial on 15m at 8 feet
The far-field plot for this antenna over good ground appears below.
106
ANTENNAS FOR 100 POUND DXPEDITIONS
Buddipole vertical with L-radial on 15m
Buddipole vertical with L-radial on 15m
Figure 127 Buddipole vertical with L-radial on 15m at 8 feet over good ground
The far-field plot for this antenna over poor ground appears below.
Buddipole vertical with L-radial on 15m
Buddipole vertical with L-radial on 15m
Figure 128 Buddipole vertical with L-radial on 15m at 8 feet over poor ground
107
ANTENNAS FOR 100 POUND DXPEDITIONS
8.2.4 Buddipole Vertical with L-arm radial for 17m at 8 feet
The “L” for 17 meters appears below.
Figure 129 Buddipole vertical with L-radial on 17m at 8 feet
Here is the model data for this antenna
EZNEC+ ver. 5.0
Buddipole vert-L 17m at 8 ft
8/30/2007
1:23:18 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 18.1 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
Coord. (in)
X
Y
End 2
Z
1
W3E1
0,
0,
192
2
W1E2
0,
0,
214
3
W1E1
0,
0,
192
4
W3E2
0,
22,
192
Coord. (in)
Dia (in)
Ins
Conn.
X
Y
W2E1
0,
0,
214
0.75
11
1
0
0,
0,
260
0.5
11
1
0
W4E1
Z
Segs
Diel C
0,
22,
192
0.5
11
1
0
0,
93,
185
0.5
11
1
0
Total Segments: 44
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
1
% From E1
0.00
Actual Pos.
% From E1
4.55
Amplitude
Seg
(V/A)
1
Phase
Type
(deg.)
1
0
I
-------------- LOADS (RLC Type) -------------No.
Specified Pos.
Wire #
1
108
1
% From E1
100.00
Actual Pos.
% From E1
95.45
Seg
11
Thk(in)
R
(ohms)
Open
L
(uH)
1.72
C
R Freq
(pF)
(MHz)
Open
18.1
Type
Par
ANTENNAS FOR 100 POUND DXPEDITIONS
2
3
100.00
95.45
11
Open
3.73
Open
18.1
Par
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
The SWR plot for this antenna appears below.
Measurement not taken
SWR predicted by model
SWR measured by AntennaSmith
Figure 130 SWR for Buddipole vertical with L-radial on 17m at 8 feet
The far-field plot for this antenna over good ground appears below.
109
ANTENNAS FOR 100 POUND DXPEDITIONS
Buddipole vertical with L-radial on 17m
Buddipole vertical with L-radial on 17m
Figure 131 Buddipole vertical with L-radial on 17m at 8 feet over good ground
The far-field plot for this antenna over poor ground appears below.
Buddipole vertical with L-radial on 17m
Buddipole vertical with L-radial on 17m
Figure 132 Buddipole vertical with L-radial on 17m at 8 feet over poor ground
110
ANTENNAS FOR 100 POUND DXPEDITIONS
8.2.5 Buddipole Vertical with L-arm radial for 20m at 8 feet
The “L” for 20 meters appears below.
Figure 133 Buddipole vertical with L-radial on 20m at 8 feet
Here is the model data for this antenna.
EZNEC+ ver. 5.0
Buddipole vert-L 20m at 8 ft
8/30/2007
1:46:43 PM
--------------- ANTENNA DESCRIPTION -------------Frequency = 14.1 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
Coord. (in)
End 2
X
Y
Z
Conn.
1
W3E1
0,
0,
192
W2E1
2
W1E2
0,
0,
214
3
W1E1
0,
0,
192
4
W3E2
0,
22,
192
W4E1
Coord. (in)
Dia (in)
Z
Segs
Ins
X
Y
0,
0,
214
0.75
11
Diel C
1
Thk(in)
0
0,
0,
267
0.5
11
1
0
0,
22,
192
0.5
11
1
0
0,
89,
192
0.5
11
1
0
Total Segments: 44
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
1
% From E1
0.00
Actual Pos.
% From E1
4.55
Amplitude
Seg
(V/A)
1
Phase
Type
(deg.)
1
0
I
-------------- LOADS (RLC Type) -------------No.
Specified Pos.
Wire #
% From E1
Actual Pos.
% From E1
Seg
R
L
C
R Freq
(ohms)
(uH)
(pF)
(MHz)
Type
1
1
100.00
95.45
11
Open
5.99
Open
14.1
Par
2
3
100.00
95.45
11
Open
3.73
Open
14.1
Par
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
111
ANTENNAS FOR 100 POUND DXPEDITIONS
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
The SWR plot for this antenna appears below.
Measurement not taken
SWR predicted by model
SWR measured by AntennaSmith
Figure 134 SWR for Buddipole vertical with L-radial on 20m at 8 feet
Note that the matching for this antenna required an 8:1 transformer matching 50 ohms to
6.25 ohms just to get a 2:1 SWR over 50 KHz. Tuning is very sharp on this antenna because
the radiation resistance is very low and capacitive and inductive reactance values can vary
greatly compared to that low ohmic resistance. This is basically an unusable configuration at
8 feet.
The far-field plot for this antenna over good ground appears below.
112
ANTENNAS FOR 100 POUND DXPEDITIONS
Buddipole vertical with L-radial on 20m
Buddipole vertical with L-radial on 20m
Figure 135 Buddipole vertical with L-radial on 20m at 8 feet over good ground
The far-field plot for this antenna over poor ground appears below.
Buddipole vertical with L-radial on 20m
Buddipole vertical with L-radial on 20m
Figure 136 Buddipole vertical with L-radial on 20m at 8 feet over poor ground
113
ANTENNAS FOR 100 POUND DXPEDITIONS
8.3
Buddipole Vertical with L-arm radial at 16 feet
The antenna systems described above are now brought up to 16 feet. The models below are
simply translated up to this new height. The higher feed point and element heights make a
big difference as evidenced by the plots below.
This system has the same problems as the “L” at 8 feet. The center of gravity of the antenna
is far from the mast, the patterns are bizarre, and it still doesn’t match well on 20 meters.
The problem common with all these antennas is they are very short for these lower bands.
The 6 foot stainless steel whips are simply too short to provide a good radiator for 15 meters
and below. This is discussed more extensively in the Long Buddipole section.
In the mean time, the “L” configuration at 16 feet is explored below.
8.3.1 Buddipole Vertical with L-arm radial for 10m at 16 feet
The “L” for 10 meters appears below.
Figure 137 Buddipole vertical with L-radial on 10m at 16 feet
Here is the model data for this antenna.
EZNEC+ ver. 5.0
Buddipole vert-L 10m at 16 ft
8/30/2007
2:19:59 PM
--------------- ANTENNA DESCRIPTION -------------Frequency = 28.3 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
Conn.
114
End 1
Coord. (in)
X
Y
Z
1
W3E1
0,
0,
288
2
W1E2
0,
0,
310
3
W1E1
0,
0,
288
4
W3E2
0,
22,
288
End 2
Conn.
W2E1
W4E1
Coord. (in)
Dia (in)
Z
Segs
Ins
Diel C
Thk(in)
X
Y
0,
0,
310
0.75
11
1
0
0,
0,
376
0.5
11
1
0
0,
22,
288
0.5
11
1
0
0,
93,
288
0.5
11
1
0
ANTENNAS FOR 100 POUND DXPEDITIONS
Total Segments: 44
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
1
% From E1
Actual Pos.
% From E1
0.00
4.55
Amplitude
Seg
Phase
(V/A)
1
Type
(deg.)
1
0
I
-------------- LOADS (RLC Type) -------------No.
Specified Pos.
Wire #
% From E1
Actual Pos.
% From E1
R
Seg
(ohms)
L
(uH)
C
R Freq
(pF)
(MHz)
Type
1
1
100.00
95.45
11
Open
0.27
Open
28.3
Par
2
3
100.00
95.45
11
Open
0.27
Open
28.3
Par
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
The SWR plot for this antenna appears below.
SWR predicted by model
SWR measured by AntennaSmith
Figure 138 SWR for Buddipole vertical with L-radial on 10m at 16 feet
The far-field plot for this antenna over good ground appears below.
115
ANTENNAS FOR 100 POUND DXPEDITIONS
Buddipole vertical with L-radial on 10m
Buddipole vertical with L-radial on 10m
Figure 139 Buddipole vertical with L-radial on 10m at 16 feet over good ground
The far-field plot for this antenna over poor ground appears below.
Buddipole vertical with L-radial on 10m
Buddipole vertical with L-radial on 10m
Figure 140 Buddipole vertical with L-radial on 10m at 16 feet over poor ground
116
ANTENNAS FOR 100 POUND DXPEDITIONS
8.3.2 Buddipole Vertical with L-arm radial for 12m at 16 feet
The “L” for 12 meters appears below.
Figure 141 Buddipole vertical with L-radial on 12m at 16 feet
Here is the model data for this antenna.
EZNEC+ ver. 5.0
Buddipole vert-L 12m at 16 ft
8/30/2007
2:31:37 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 24.9 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. =
--------------- WIRES --------------No.
End 1
Conn.
Coord. (in)
X
Y
End 2
Z
1
W3E1
0,
0,
288
2
W1E2
0,
0,
310
3
W1E1
0,
0,
288
4
W3E2
0,
22,
288
Conn.
W2E1
W4E1
Coord. (in)
Dia (in)
Z
Segs
Ins
X
Y
Diel C
Thk(in)
0,
0,
310
0.75
11
1
0
0,
0,
381
0.5
11
1
0
0,
22,
288
0.5
11
1
0
0,
93,
288
0.5
11
1
0
Total Segments: 44
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
1
% From E1
0.00
Actual Pos.
% From E1
4.55
Amplitude
Seg
(V/A)
1
Phase
Type
(deg.)
1
0
I
-------------- LOADS (RLC Type) -------------No.
Specified Pos.
Wire #
% From E1
Actual Pos.
% From E1
Seg
R
(ohms)
L
(uH)
C
R Freq
(pF)
(MHz)
Type
1
1
100.00
95.45
11
Open
0.89
Open
24.9
Par
2
3
100.00
95.45
11
Open
0.27
Open
24.9
Par
No transmission lines specified
No transformers specified
No L Networks specified
117
ANTENNAS FOR 100 POUND DXPEDITIONS
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
The SWR plot for this antenna appears below.
SWR predicted by model
SWR measured by AntennaSmith
Figure 142 SWR for Buddipole vertical with L-radial on 12m at 16 feet
The far-field plot for this antenna over good ground appears below.
118
ANTENNAS FOR 100 POUND DXPEDITIONS
Buddipole vertical with L-radial on 12m
Buddipole vertical with L-radial on 12m
Figure 143 Buddipole vertical with L-radial on 12m at 16 feet over good ground
The far-field plot for this antenna over poor ground appears below.
Buddipole vertical with L-radial on 12m
Buddipole vertical with L-radial on 12m
Figure 144 Buddipole vertical with L-radial on 12m at 16 feet over poor ground
119
ANTENNAS FOR 100 POUND DXPEDITIONS
8.3.3 Buddipole Vertical with L-arm radial for 15m at 16 feet
The “L” for 15 meters appears below.
Figure 145 Buddipole vertical with L-radial on 15m at 16 feet
Here is the model data for this antenna.
EZNEC+ ver. 5.0
Buddipole vert-L 15m at 16 ft
8/30/2007
2:46:25 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 21.2 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
Coord. (in)
X
Y
Z
1
W3E1
0,
0,
288
2
W1E2
0,
0,
310
3
W1E1
0,
0,
288
4
W3E2
0,
22,
288
End 2
Conn.
W2E1
W4E1
Coord. (in)
Dia (in) Segs
Z
Ins
X
Y
Diel C
Thk(in)
0,
0,
310
0.75
11
1
0
0,
0,
377
0.5
11
1
0
0,
22,
288
0.5
11
1
0
0,
93,
288
0.5
11
1
0
Total Segments: 44
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
1
% From E1
0.00
Actual Pos.
% From E1
4.55
Amplitude
Seg
(V/A)
1
Phase
Type
(deg.)
1
0
I
-------------- LOADS (RLC Type) ------------No.
Specified Pos.
Wire #
% From E1
Actual Pos.
% From E1
L
C
R Freq
(ohms)
(uH)
(pF)
(MHz)
Type
1
1
100.00
95.45
11
Open
1.72
Open
21.2
Par
2
3
100.00
95.45
11
Open
0.89
Open
21.2
Par
No transmission lines specified
No transformers specified
No L Networks specified
120
Seg
R
ANTENNAS FOR 100 POUND DXPEDITIONS
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
The SWR plot for this antenna appears below.
SWR predicted by model
SWR measured by AntennaSmith
Figure 146 SWR for Buddipole vertical with L-radial on 15m at 16 feet
The far-field plot for this antenna over good ground appears below.
121
ANTENNAS FOR 100 POUND DXPEDITIONS
Buddipole vertical with L-radial on 15m
Buddipole vertical with L-radial on 15m
Figure 147 Buddipole vertical with L-radial on 15m at 16 feet over good ground
The far-field plot for this antenna over poor ground appears below.
Buddipole vertical with L-radial on 15m
Buddipole vertical with L-radial on 15m
Figure 148 Buddipole vertical with L-radial on 15m at 16 feet over poor ground
122
ANTENNAS FOR 100 POUND DXPEDITIONS
8.3.4 Buddipole Vertical with L-arm radial for 17m at 16 feet
The “L” for 17 meters appears below.
Figure 149 Buddipole vertical with L-radial on 17m at 16 feet
Here is the model data for this antenna.
EZNEC+ ver. 5.0
Buddipole vert-L 17m at 16 ft
8/30/2007
3:06:55 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 18.1 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES -------------No.
End 1
Conn.
Coord. (in)
X
Y
End 2
Z
1
W3E1
0,
0,
288
2
W1E2
0,
0,
310
3
W1E1
0,
0,
288
4
W3E2
0,
22,
288
Conn.
W2E1
W4E1
Coord. (in) Dia (in)
Ins
Y
0,
0,
310
0.75
11
1
0
0,
0,
358
0.5
11
1
0
22,
288
0,
0,
Z
Segs
X
91.5,
Diel C
288
Thk(in)
0.5
11
1
0
0.5
11
1
0
Total Segments: 44
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
1
% From E1
0.00
Actual Pos.
% From E1
4.55
Amplitude
Seg
(V/A)
1
Phase
Type
(deg.)
1
0
I
-------------- LOADS (RLC Type) -------------No.
Specified Pos.
Wire #
% From E1
Actual Pos.
% From E1
Seg
R
L
C
R Freq
(ohms)
(uH)
(pF)
(MHz)
Type
1
1
100.00
95.45
11
Open
1.72
Open
18.1
Par
2
3
100.00
95.45
11
Open
3.73
Open
18.1
Par
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
123
ANTENNAS FOR 100 POUND DXPEDITIONS
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
The SWR plot for this antenna appears below.
SWR predicted by model
SWR measured by AntennaSmith
Figure 150 SWR for Buddipole vertical with L-radial on 17m at 16 feet
The far-field plot for this antenna over good ground appears below.
124
ANTENNAS FOR 100 POUND DXPEDITIONS
Buddipole vertical with L-radial on 17m
Buddipole vertical with L-radial on 17m
Figure 151 Buddipole vertical with L-radial on 17m at 16 feet over good ground
The far-field plot for this antenna over poor ground appears below.
Buddipole vertical with L-radial on 17m
Buddipole vertical with L-radial on 17m
Figure 152 Buddipole vertical with L-radial on 17m at 16 feet over poor ground
125
ANTENNAS FOR 100 POUND DXPEDITIONS
8.3.5 Buddipole Vertical with L-arm radial for 20m at 16 feet
The “L” for 20 meters appears below.
Figure 153 Buddipole vertical with L-radial on 20m at 16 feet
Here is the model data for this antenna.
EZNEC+ ver. 5.0
Buddipole vert-L 20m at 16 ft
8/30/2007
3:45:25 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 14.1 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
1
W3E1
Coord. (in)
X
Y
0,
0,
End 2
Z
288
2
W1E2
0,
0,
310
3
W1E1
0,
0,
288
4
W3E2
0,
22,
288
Coord. (in)
Conn. X
Y
Dia (in)
Segs
Z
0,
Ins
Diel C
310
0.75
11
Thk(in)
W2E1
0,
1
0
0,
0,
364
0.5
11
1
0
W4E1
0,
22,
288
0.5
11
1
0
0,
90,
288
0.5
11
1
0
Total Segments: 44
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
1
% From E1
0.00
Actual Pos.
% From E1
4.55
Seg
Amplitude
(V/A)
1
Phase
Type
(deg.)
1
0
I
-------------- LOADS (RLC Type) -------------No.
Type
Specified Pos.
Wire #
% From E1
Actual Pos.
% From E1
L
C
R Freq
(ohms)
(uH)
(pF)
(MHz)
1
1
100.00
95.45
11
Open
5.99
Open
14.1
Par
2
3
100.00
95.45
11
Open
3.73
Open
14.1
Par
No transmission lines specified
126
Seg
R
ANTENNAS FOR 100 POUND DXPEDITIONS
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
The SWR plot for this antenna appears below.
Measurement not taken
SWR predicted by model
SWR measured by AntennaSmith
Figure 154 SWR for Buddipole vertical with L-radial on 20m at 16 feet
Again, even at 16 feet this is a very difficult antenna to match to 50 ohms. Though the
height may be satisfactory for an antenna design like this, the element lengths are simply too
short for this band. A similarly designed antenna with longer whips is discussed later and the
longer element lengths make a big difference.
The far-field plot for this antenna over good ground appears below.
127
ANTENNAS FOR 100 POUND DXPEDITIONS
Buddipole vertical with L-radial on 20m
Buddipole vertical with L-radial on 20m
Figure 155 Buddipole vertical with L-radial on 20m at 16 feet over good ground
The far-field plot for this antenna over poor ground appears below.
Buddipole vertical with L-radial on 20m
Buddipole vertical with L-radial on 20m
Figure 156 Buddipole vertical with L-radial on 20m at 16 feet over poor ground
128
ANTENNAS FOR 100 POUND DXPEDITIONS
8.4
Buddipole vertical with single sloping radial at 16 feet
The previous Buddipole antennas were modeled without the effects of the mast. With this
set of models we now begin to route portions of the antenna in the proximity of the mast so
we can no longer ignore this big piece of metal. In fact, experiments using the modeling
software show that the mast can have a significant affect on the characteristics and
performance of the system it supports. Beginning with these sets of models a one inch mast
will be included in the calculations that is specified to come just short of feed point and a
few inches off the ground (to ensure we do not overstate the effects on either aspect). This
mast definition is larger in diameter than the standard Buddipole mast systems but a little
smaller than “painters poles” that are sometimes used for masts.
We are still using the short stainless steel whips for these antenna designs. The “wires” run
down at a 45 degree angle can be either arms and whips (using the Rotating Arm Kit), or be
actual wires. The larger diameter conductors are modeled. In the plots below.
8.4.1 Buddipole vertical with 1 radial for 10m at 16 feet
The vertical for 10 meters appears below. Here is the model data for this antenna.
Figure 157 Buddipole vertical for 10m with 1 radial
EZNEC+ ver. 5.0
BP vert 1 rad 10m at 16 ft
9/1/2007
12:09:16 AM
--------------- ANTENNA DESCRIPTION --------------Frequency = 28.3 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
Coord. (in)
X
Y
End 2
Z
Coord. (in)
Dia (in)
Z
Segs
Ins
Conn.
X
Y
Diel C
Thk(in)
W2E1
0,
0,
214
0.75
11
1
0
1
W3E1
0,
0,
192
2
W1E2
0,
0,
214
0,
0,
280
0.5
11
1
0
3
W1E1
0,
0,
192
0,
69,
123
0.5
11
1
0
129
ANTENNAS FOR 100 POUND DXPEDITIONS
4
0,
0,
6
0,
0,
186
1
11
1
0
Total Segments: 44
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
1
% From E1
Actual Pos.
% From E1
0.00
4.55
Amplitude
Seg
Phase
(V/A)
1
Type
(deg.)
1
0
-------------- LOADS (RLC Type) -------------No.
Specified Pos.
Wire #
1
1
% From E1
Actual Pos.
% From E1
100.00
95.45
R
Seg
11
L
C
R Freq
(ohms)
(uH)
(pF)
(MHz)
Open
0.27
Open
28.3
Type
Par
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
This model yields the following SWR plot.
SWR predicted by model
SWR measured by AntennaSmith
Figure 158 SWR for Buddipole vertical with 1 radial on 10m at 16 feet
The far-field plot for this antenna over good ground appears below.
130
ANTENNAS FOR 100 POUND DXPEDITIONS
Buddipole Vertical on 10m with 1 radial
Buddipole Vertical on 10m with 1 radial
Figure 159 Buddipole vertical with 1 radial on 10m at 16 feet over good ground
The far-field plot for this antenna over poor ground appears below.
Buddipole Vertical on 10m with 1 radial
Buddipole Vertical on 10m with 1 radial
Figure 160 Buddipole vertical with 1 radial on 10m at 16 feet over poor ground
131
ANTENNAS FOR 100 POUND DXPEDITIONS
8.4.2 Buddipole vertical with 1 radial for 12m at 8 feet
The vertical for 12 meters appears below.
Figure 161 Buddipole vertical for 12m with 1 radial
Here is the model data for this antenna.
EZNEC+ ver. 5.0
BP vert 1 rad 12m at 16 ft
9/1/2007
12:44:44 AM
--------------- ANTENNA DESCRIPTION --------------Frequency = 24.9 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
Coord. (in)
X
Y
End 2
Z
Conn.
W2E1
Coord. (in)
X
Y
Dia (in)
Segs
Z
Ins
Diel C
1
W3E1
0,
0,
192
0,
0,
214
0.75
11
1
0
2
W1E2
0,
0,
214
0,
0,
277
0.5
11
1
0
3
W1E1
0,
0,
192
0,
78,
114
0.5
11
1
0
0,
0,
6
0,
0,
186
1
11
1
0
4
Total Segments: 44
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
1
% From E1
0.00
Actual Pos.
% From E1
4.55
Amplitude
Seg
Phase
(V/A)
1
Type
(deg.)
1
0
I
-------------- LOADS (RLC Type) -------------No.
Specified Pos.
Wire #
1
1
% From E1
100.00
Actual Pos.
% From E1
95.45
No transmission lines specified
No transformers specified
No L Networks specified
132
Thk(in)
Seg
11
R
L
C
R Freq
(ohms)
(uH)
(pF)
(MHz)
Open
0.89
Open
28.3
Type
Par
ANTENNAS FOR 100 POUND DXPEDITIONS
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
This model yields the following SWR plot.
SWR predicted by model
SWR measured by AntennaSmith
Figure 162 SWR for Buddipole vertical with 1 radial on 12m at 16 feet
The far-field plot for this antenna over good ground appears below.
133
ANTENNAS FOR 100 POUND DXPEDITIONS
Buddipole Vertical on 12m with 1 radial
Buddipole Vertical on 12m with 1 radial
Figure 163 Buddipole vertical with 1 radial on 12m at 16 feet over good ground
The far-field plot for this antenna over poor ground appears below.
Buddipole Vertical on 12m with 1 radial
Buddipole Vertical on 12m with 1 radial
Figure 164 Buddipole vertical with 1 radial on 12m at 16 feet over poor ground
134
ANTENNAS FOR 100 POUND DXPEDITIONS
8.4.3 Buddipole vertical with 1 radial for 15m at 8 feet
The vertical for 15 meters appears below.
Figure 165 Buddipole vertical for 15m with 1 radial
Below is the model data for this antenna.
EZNEC+ ver. 5.0
BP vert 1 rad 15m at 16 ft
9/2/2007
12:08:05 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 21.2 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Coord. (in)
Conn.
End 2
X
Y
1
W3E1
0,
0,
192
2
W1E2
0,
0,
3
W1E1
0,
0,
4
Z
Conn.
Coord. (in)
Dia (in)
Segs
X
Y
0,
0,
214
0.75
11
1
0
214
0,
0,
273
0.5
11
1
0
0,
192
0,
94,
98
0.5
11
1
0
0,
6
0,
0,
186
1
11
1
0
W2E1
Z
Ins
Diel C
Thk(in)
Total Segments: 44
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
1
Actual Pos.
% From E1
0.00
% From E1
4.55
Amplitude
Seg
Phase
(V/A)
1
Type
(deg.)
1
0
I
-------------- LOADS (RLC Type) -------------No.
Specified Pos.
Wire #
1
1
% From E1
100.00
Actual Pos.
% From E1
95.45
Seg
11
R
(ohms)
Open
L
(uH)
1.72
C
R Freq
(pF)
Open
Type
(MHz)
21.2
Par
No transmission lines specified
135
ANTENNAS FOR 100 POUND DXPEDITIONS
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
The SWR plot for this antenna appears below.
SWR predicted by model
SWR measured by AntennaSmith
Figure 166 SWR for Buddipole vertical with 1 radial on 15m at 16 feet
The far-field plot for this antenna over good ground appears below.
136
ANTENNAS FOR 100 POUND DXPEDITIONS
Buddipole Vertical on 15m with 1 radial
Buddipole Vertical on 15m with 1 radial
Figure 167 Buddipole vertical with 1 radial on 15m at 16 feet over good ground
The far-field plot for this antenna over poor ground appears below.
Buddipole Vertical on 15m with 1 radial
Buddipole Vertical on 15m with 1 radial
Figure 168 Buddipole vertical with 1 radial on 15m at 16 feet over poor ground
137
ANTENNAS FOR 100 POUND DXPEDITIONS
8.4.4 Buddipole vertical with 1 radial for 17m at 16 feet
The vertical for 17 meters appears below.
Figure 169 Buddipole vertical for 17m with 1 radial
The model data for this antenna appears below.
EZNEC+ ver. 5.0
BP vert 1 rad 17m at 16 ft
9/2/2007
12:23:36 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 18.1 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
Coord. (in)
End 2
X
Y
1
W3E1
0,
0,
192
2
W1E2
0,
0,
3
W1E1
0,
0,
4
Z
Conn.
Coord. (in)
Dia (in)
Segs
X
Y
0,
0,
214
0.75
11
1
0
214
0,
0,
286
0.5
11
1
0
0,
192
0,
112,
76
0.5
11
1
0
0,
6
0,
0,
186
1
11
1
0
W2E1
Z
Ins
Diel C
Thk(in)
Total Segments: 44
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
Actual Pos.
% From E1
1
% From E1
0.00
4.55
Amplitude
Seg
Phase
(V/A)
1
Type
(deg.)
1
0
I
-------------- LOADS (RLC Type) -------------No. Specified Pos.
1
Wire #
% From E1
1
100.00
Actual Pos.
% From E1
95.45
No transmission lines specified
138
Seg
11
R
L
C
R Freq
(ohms)
(uH)
(pF)
(MHz)
Open
1.72
Open
18.1
Type
Par
ANTENNAS FOR 100 POUND DXPEDITIONS
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
The SWR plot for this antenna appears below.
SWR predicted by model
SWR measured by AntennaSmith
Figure 170 SWR for Buddipole vertical with 1 radial on 17m at 16 feet
The far-field plot for this antenna over good ground appears below.
139
ANTENNAS FOR 100 POUND DXPEDITIONS
Buddipole Vertical on 17m with 1 radial
Buddipole Vertical on 17m with 1 radial
Figure 171 Buddipole vertical with 1 radial on 17m at 16 feet over good ground
The far-field plot for this antenna over poor ground appears below.
Buddipole Vertical on 17m with 1 radial
Buddipole Vertical on 17m with 1 radial
Figure 172 Buddipole vertical with 1 radial on 17m at 16 feet over poor ground
140
ANTENNAS FOR 100 POUND DXPEDITIONS
8.4.5 Buddipole vertical with 1 radial for 20m at 16 feet
The vertical for 20 meters appears below.
Figure 173 Buddipole vertical for 20m with 1 radial
Here is the model data for this antenna.
EZNEC+ ver. 5.0
BP vert 1 rad 20m at 16 ft
9/2/2007
12:36:54 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 14.1 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
Coord. (in)
X
Y
End 2
Z
Conn.
Dia (in)
Z
Segs
Ins
Diel C
Thk(in)
X
Y
0,
0,
214
0.75
11
1
0
262
0.5
11
1
0
1
W3E1
0,
0,
192
2
W1E2
0,
0,
214
0,
0,
3
W1E1
0,
0,
192
0,
142,
50
0.5
11
1
0
0,
0,
6
0,
0,
186
1
11
1
0
4
W2E1
Coord. (in)
Total Segments: 44
-------------- SOURCES ------------No.
Specified Pos.
Wire #
1
Actual Pos.
% From E1
1
% From E1
0.00
4.55
Amplitude
Seg
Phase
(V/A)
1
Type
(deg.)
1
0
I
-------------- LOADS (RLC Type) -------------No.
1
Specified Pos.
Wire #
% From E1
1
100.00
Actual Pos.
% From E1
95.45
Seg
11
C
R Freq
(ohms)
R
(uH)
L
(pF)
(MHz)
Open
5.99
Open
14.1
Type
Par
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
141
ANTENNAS FOR 100 POUND DXPEDITIONS
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
The SWR plot for this antenna appears below.
SWR predicted by model
SWR measured by AntennaSmith
Figure 174 SWR for Buddipole vertical with 1 radial on 20m at 16 feet
The far-field plot for this antenna over good ground appears below.
142
ANTENNAS FOR 100 POUND DXPEDITIONS
Buddipole Vertical on 20m with 1 radial
Buddipole Vertical on 20m with 1 radial
Figure 175 Buddipole vertical with 1 radial on 20m at 16 feet over good ground
The far-field plot for this antenna over poor ground appears below.
Buddipole Vertical on 20m with 1 radial
Buddipole Vertical on 20m with 1 radial
Figure 176 Buddipole vertical with 1 radial on 20m at 16 feet over poor ground
143
ANTENNAS FOR 100 POUND DXPEDITIONS
9 LONG BUDDIPOLE
The Standard Buddipole system used just the compliment of parts included in the Buddipole
Deluxe Package (plus TRSB). This chapter discusses options for antenna designs when extra
components or substitute components are used.
9.1
Differences between the Standard Buddipole and Long Buddipole
One of the biggest problems with the antennas constructed from the Standard Buddipole
system is the length of the whips. The 5.5 foot stainless steel whips are just too short to
make good antennas on the lower bands. Buddipole offers longer whips into two forms:
•
Shock-cord whips – These whips are constructed from solid aluminum pieces that
are held together by a stretchy nylon rope in the middle. Similar to tent poles, these
whips can be pulled apart for storage, or strung together to make a virtually
unbreakable radiator. The advantages of these whips is their sturdiness; the
disadvantage is they cannot be adjusted as finely as a regular whip. Costs range from
$36 to $60 depending on length.
•
Long telescopic whips – These whips extend to 9 feet 4 inches in length, nearly
double the standard stainless steel whip. They collapse to about 22 inches so they can
be stored and packed with other Buddipole parts. They are surprisingly resilient for
their length. A long telescopic whip is $18 as of this writing.
The lengths of elements can also be increased by adding extra antenna arms. Each 22 inch
aluminum piece not only adds length to an element but also adds bandwidth as the pieces are
0.75 inches in diameter (instead of the much smaller diameter whip sections).
The designs below will use the long telescopic whips instead of the shorter stainless steel
whips. Designs will also incorporated 0, 1, or 2 arms as necessary to eliminate the need for
loading coils. No coils are used in the following antenna system designs!
Each antenna has one radial running down from the feed point at an angle of 45 degrees (or
less). In practice, the antenna is constructed so that the vertical radiator is full-sized based on
the formula 234/f and the length of the radial is adjusted to bring the antenna into a good
match for 50 ohms.
9.2
Buddipole full-sized vertical with 1 radial 8 feet
9.2.1 Buddipole full-sized vertical with 1 radial for 10m at 8 feet
The vertical for 10 meters appears below. We assume a whip can be used as the radial so it
has a large diameter. Here is the model data for this antenna.
144
ANTENNAS FOR 100 POUND DXPEDITIONS
Figure 177 Buddipole full-sized vertical for 10m with 1 radial
Below is the model data for this antenna.
EZNEC+ ver. 5.0
BP long vert 1 rad 10m at 8ft
9/3/2007
7:20:56 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 28.3 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
Coord. (in)
X
Y
End 2
Z
Conn.
X
Y
Dia (in)
Z
Segs
Diel C
Ins
Thk(in)
1
W3E1
0,
0,
96
0,
0,
118
0.75
11
1
0
2
W1E2
0,
0,
118
0,
0,
198
0.5
11
1
0
3
W1E1
0,
0,
96
0,
69,
23
0.5
11
1
0
0,
0,
6
0,
0,
90
1
11
1
0
4
W2E1
Coord. (in)
Total Segments: 44
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
% From E1
1
Actual Pos.
% From E1
0.00
4.55
Amplitude
Seg
(V/A)
1
1
Phase
Type
(deg.)
0
I
No loads specified
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
145
ANTENNAS FOR 100 POUND DXPEDITIONS
The SWR plot for this antenna appears below.
Measurement not taken
SWR predicted by model
SWR measured by AntennaSmith
Figure 178 SWR for BP full-sized vertical with 1 radial on 10m at 8 feet
The far-field plot for this antenna over good ground appears below.
146
ANTENNAS FOR 100 POUND DXPEDITIONS
BP full-sized vertical on 10m with 1 radial
BP Full-sized vertical on 10m with 1 radial
Figure 179 BP full-sized vertical with 1 radial on 10m at 8 feet over good ground
The far-field plot for this antenna over poor ground appears below.
BP Full-sized vertical on 10m with 1 radial
BP Full-sized vertical on 10m with 1 radial
Figure 180 Buddipole full-sized vertical, 1 radial on 10m at 8 feet over poor ground
147
ANTENNAS FOR 100 POUND DXPEDITIONS
9.2.2 Buddipole full-sized vertical with 1 radial for 12m at 8 feet
The vertical for 12 meters appears below.
Figure 181 Buddipole full-sized vertical for 12m with 1 radial
Below is the model data for this antenna.
EZNEC+ ver. 5.0
BP long vert 1 rad 12m at 8ft
9/3/2007
7:36:41 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 24.9 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Insulation
Conn.
Thk(in)
C
Coord. (in)
X
Y
End 2
Z
Conn.
Dia (in)
X
Y
Z
Diel
0,
0,
118
0.75
11
1
0
W3E1
0,
0,
96
2
W1E2
0,
0,
118
0,
0,
209
0.5
11
1
0
3
W1E1
0,
0,
96
0,
81,
14
0.5
11
1
0
0,
0,
6
0,
0,
90
1
11
1
0
Total Segments: 44
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
% From E1
1
0.00
Actual Pos.
% From E1
4.55
No loads specified
No transmission lines specified
No transformers specified
148
Segs
1
4
W2E1
Coord. (in)
Seg
1
Amplitude
(V/A)
1
Phase
Type
(deg.)
0
I
ANTENNAS FOR 100 POUND DXPEDITIONS
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.001
5
Height
R Coord.
(in)
(in)
0
0
The SWR plot for this antenna appears below.
Measurement not taken
SWR predicted by model
SWR measured by AntennaSmith
Figure 182 SWR for BP full-sized vertical with 1 radial on 12m at 8 feet
The far-field plot for this antenna over good ground appears below.
149
ANTENNAS FOR 100 POUND DXPEDITIONS
BP full-sized vertical on 12m with 1 radial
BP Full-sized vertical on 12m with 1 radial
Figure 183 BP full-sized vertical with 1 radial on 12m at 8 feet over good ground
The far-field plot for this antenna over poor ground appears below.
BP Full-sized vertical on 12m with 1 radial
BP Full-sized vertical on 12m with 1 radial
Figure 184 Buddipole full-sized vertical, 1 radial on 12m at 8 feet over poor ground
150
ANTENNAS FOR 100 POUND DXPEDITIONS
9.2.3 Buddipole full-sized vertical with 1 radial for 15m at 8 feet
The vertical for 15 meters appears below.
Figure 185 Buddipole full-sized vertical for 15m with 1 radial
Below is the model data for this antenna.
EZNEC+ ver. 5.0
BP long vert 1 rad 15m at 8ft
9/3/2007
7:48:20 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 21.2 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
Coord. (in)
X
Y
End 2
Z
Conn.
X
Y
Dia (in)
Z
Segs
Ins
Diel C
Thk(in)
1
W3E1
0,
0,
96
0,
0,
118
0.75
11
1
0
2
W1E2
0,
0,
118
0,
0,
230
0.5
11
1
0
3
W1E1
0,
0,
96
0,
129,
36
0.5
11
1
0
0,
0,
6
0,
0,
90
1
11
1
0
4
W2E1
Coord. (in)
Total Segments: 44
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
% From E1
1
0.00
Actual Pos.
% From E1
4.55
Seg
1
Amplitude
(V/A)
1
Phase
Type
(deg.)
0
I
No loads specified
No transmission lines specified
No transformers specified
151
ANTENNAS FOR 100 POUND DXPEDITIONS
No L Networks specified
Ground type is Real, High-Accuracy
-------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
The SWR plot for this antenna appears below.
Measurement not taken
SWR predicted by model
SWR measured by AntennaSmith
Figure 186 SWR for BP full-sized vertical with 1 radial on 10m at 8 feet
The far-field plot for this antenna over good ground appears below.
152
ANTENNAS FOR 100 POUND DXPEDITIONS
BP full-sized vertical on 15m with 1 radial
BP Full-sized vertical on 15m with 1 radial
Figure 187 BP full-sized vertical with 1 radial on 15m at 8 feet over good ground
The far-field plot for this antenna over poor ground appears below.
BP Full-sized vertical on 15m with 1 radial
BP Full-sized vertical on 15m with 1 radial
Figure 188 Buddipole full-sized vertical, 1 radial on 15m at 8 feet over poor ground
153
ANTENNAS FOR 100 POUND DXPEDITIONS
9.2.4 Buddipole full-sized vertical with 1 radial for 17m at 8 feet
The vertical for 17 meters appears below.
Figure 189 Buddipole full-sized vertical for 17m with 1 radial
Below is the model data for this antenna.
EZNEC+ ver. 5.0
BP long vert 1 rad 17m at 8ft
9/3/2007
7:54:27 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 18.1 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
-------------- WIRES --------------No.
End 1
Insulation
Conn.
Coord. (in)
X
Y
End 2
Z
Conn.
X
Y
Dia (in)
Z
Diel C
Thk(in)
1
W3E1
0,
0,
96
0,
0,
139
0.75
11
1
0
W1E2
0,
0,
139
0,
0,
251
0.5
11
1
0
3
W1E1
0,
0,
96
0,
152,
36
0.5
11
1
0
0,
0,
6
0,
0,
90
1
11
1
0
Total Segments: 44
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
% From E1
1
0.00
Actual Pos.
% From E1
4.55
No loads specified
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
154
Segs
2
4
W2E1
Coord. (in)
Seg
1
Amplitude
(V/A)
1
Phase
Type
(deg.)
0
I
ANTENNAS FOR 100 POUND DXPEDITIONS
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
The SWR plot for this antenna appears below.
Measurement not taken
SWR predicted by model
SWR measured by AntennaSmith
Figure 190 SWR for BP full-sized vertical with 1 radial on 17m at 8 feet
The far-field plot for this antenna over good ground appears below.
155
ANTENNAS FOR 100 POUND DXPEDITIONS
BP full-sized vertical on 17m with 1 radial
BP Full-sized vertical on 17m with 1 radial
Figure 191 BP full-sized vertical with 1 radial on 10m at 8 feet over good ground
The far-field plot for this antenna over poor ground appears below.
BP Full-sized vertical on 17m with 1 radial
BP Full-sized vertical on 17m with 1 radial
Figure 192 Buddipole full-sized vertical, 1 radial on 17m at 8 feet over poor ground
156
ANTENNAS FOR 100 POUND DXPEDITIONS
9.2.5 Buddipole full-sized vertical with 1 radial for 20m at 8 feet
The vertical for 20 meters appears below.
Figure 193 Buddipole full-sized vertical for 20m with 1 radial
Below is the model data for this antenna.
EZNEC+ ver. 5.0
BP long vert 1 rad 20m at 8ft
9/3/2007
8:02:38 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 14 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
Coord. (in)
End 2
X
Y
1
W3E1
0,
0,
96
2
W1E2
0,
0,
3
W1E1
0,
0,
4
Z
Conn.
Coord. (in)
Dia (in)
Diel C
Ins
X
Y
0,
0,
182
0.75
11
1
0
182
0,
0,
294
0.5
11
1
0
0,
96
0,
198,
36
0.5
11
1
0
0,
6
0,
0,
90
1
11
1
0
W2E1
Z
Segs
Thk(in)
Total Segments: 44
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
% From E1
1
0.00
Actual Pos.
% From E1
4.55
Seg
1
Amplitude
(V/A)
1
Phase
Type
(deg.)
0
I
No loads specified
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA ---------------
157
ANTENNAS FOR 100 POUND DXPEDITIONS
No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
The SWR plot for this antenna appears below.
Measurement not taken
SWR predicted by model
SWR measured by AntennaSmith
Figure 194 SWR for BP full-sized vertical with 1 radial on 20m at 8 feet
The far-field plot for this antenna over good ground appears below.
158
ANTENNAS FOR 100 POUND DXPEDITIONS
BP full-sized vertical on 20m with 1 radial
BP Full-sized vertical on 20m with 1 radial
Figure 195 BP full-sized vertical with 1 radial on 20m at 8 feet over good ground
The far-field plot for this antenna over poor ground appears below.
BP Full-sized vertical on 20m with 1 radial
BP Full-sized vertical on 20m with 1 radial
Figure 196 Buddipole full-sized vertical, 1 radial on 20m at 8 feet over poor ground
159
ANTENNAS FOR 100 POUND DXPEDITIONS
9.3
Buddipole full-sized vertical with 4 radials at 8 feet
With this chapter we have fixed one of the big problems with previous designs: we have
lengthened the whips for the element(s). In fact, we have substituted extra “arms” and long
whips for the coils. No coils are necessary for 20 meters and up.
The other problem we have faced is the poor radial system. One sloping radial gives us a
bizarre pattern and a generally poor return. Supplying four radials in place of that single
radial makes a world of difference, as evidenced by the plots below. Even antennas at 8 feet
perform very well with these extra radials.
9.3.1 Buddipole full-sized vertical with 4 radials for 10m at 8 feet
The vertical for 10 meters appears below.
Figure 197 Buddipole full-sized vertical for 10m with 4 radials
Below is the model data for this antenna.
EZNEC+ ver. 5.
BP long vert 4 rad 10m at 8ft
9/3/2007
9:23:05 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 28.3 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
Coord. (in)
X
Y
End 2
Z
Conn.
Dia (in)
X
Y
0,
0,
118
0.75
Segs
Z
Ins
Diel C
Thk(in)
11
1
0
1
W3E1
0,
0,
96
2
W1E2
0,
0,
118
0,
0,
198
0.5
11
1
0
3
W4E1
0,
0,
96
0,
69,
23
#12
11
1
0
4
W5E1
0,
0,
96
-69,
0,
23
#12
11
1
0
5
W6E1
0,
0,
96
0,
-69,
23
#12
11
1
0
6
W1E1
0,
0,
96
69,
0,
23
#12
11
1
0
0,
0,
6
0,
0,
90
1
11
1
0
7
160
W2E1
Coord. (in)
ANTENNAS FOR 100 POUND DXPEDITIONS
Total Segments: 77
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
% From E1
1
Actual Pos.
% From E1
0.00
4.55
Amplitude
Seg
(V/A)
1
1
Phase
Type
(deg.)
0
I
No loads specified
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
The SWR plot for this antenna appears below.
Measurement not taken
SWR predicted by model
SWR measured by AntennaSmith
Figure 198 SWR for BP full-sized vertical with 4 radials on 10m at 8 feet
The far-field plot for this antenna over good ground appears below.
161
ANTENNAS FOR 100 POUND DXPEDITIONS
BP full-sized vertical on 10m with 4 radials
BP Full-sized vertical on 10m with 4 radials
Figure 199 BP full-sized vertical with 4 radials on 10m at 8 feet over good ground
The far-field plot for this antenna over poor ground appears below.
BP Full-sized vertical on 10m with 4 radial
BP Full-sized vertical on 10m with 4 radials
Figure 200 Buddipole full-sized vertical, 4 radials on 10m at 8 feet over poor ground
162
ANTENNAS FOR 100 POUND DXPEDITIONS
9.3.2 Buddipole full-sized vertical with 4 radials for 12m at 8 feet
The vertical for 12 meters appears below.
Figure 201 Buddipole full-sized vertical for 12m with 4 radials
Below is the model data for this antenna.
EZNEC+ ver. 5.0
BP long vert 4 rad 12m at 8ft
9/3/2007
9:35:03 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 24.9 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
Coord. (in)
X
Y
End 2
Z
Conn.
Dia (in)
X
Y
0,
0,
118
0.75
0,
0,
209
Segs
Z
Ins
Diel C
Thk(in)
11
1
0
0.5
11
1
0
1
W3E1
0,
0,
96
2
W1E2
0,
0,
118
3
W4E1
0,
0,
96
0,
81,
14
#12
11
1
0
4
W5E1
0,
0,
96
-81,
0,
14
#12
11
1
0
5
W6E1
0,
0,
96
0,
-81,
14
#12
11
1
0
6
W1E1
0,
0,
96
81,
0,
14
#12
11
1
0
0,
0,
6
0,
0,
90
1
11
1
0
7
W2E1
Coord. (in)
Total Segments: 77
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
% From E1
1
0.00
Actual Pos.
% From E1
4.55
Seg
1
Amplitude
(V/A)
1
Phase
Type
(deg.)
0
I
No loads specified
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
163
ANTENNAS FOR 100 POUND DXPEDITIONS
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.001
5
Height
R Coord.
(in)
(in)
0
0
The SWR plot for this antenna appears below.
Measurement not taken
SWR predicted by model
SWR measured by AntennaSmith
Figure 202 SWR for BP full-sized vertical with 4 radial on 12m at 8 feet
The far-field plot for this antenna over good ground appears below.
164
ANTENNAS FOR 100 POUND DXPEDITIONS
BP full-sized vertical on 12m with 4 radials
BP Full-sized vertical on 12m with 4 radials
Figure 203 BP full-sized vertical with 4 radial on 12m at 8 feet over good ground
The far-field plot for this antenna over poor ground appears below.
BP Full-sized vertical on 12m with 4 radials
BP Full-sized vertical on 12m with 4 radials
Figure 204 Buddipole full-sized vertical, 4 radials on 12m at 8 feet over poor ground
165
ANTENNAS FOR 100 POUND DXPEDITIONS
9.3.3 Buddipole full-sized vertical with 4 radial for 15m at 8 feet
The vertical for 15 meters appears below.
Figure 205 Buddipole full-sized vertical for 15m with 4 radials
Below is the model data for this antenna.
EZNEC+ ver. 5.0
BP long vert 4 rad 15m at 8ft
9/3/2007
9:51:55 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 21.2 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
Coord. (in)
X
Y
End 2
Z
1
W3E1
0,
0,
96
2
W1E2
0,
0,
118
Conn.
W2E1
Coord. (in)
Dia (in)
Z
Ins
X
Y
Diel C
0,
0,
118
0.75
11
1
0
0,
0,
230
0.5
11
1
0
Thk(in)
3
W4E1
0,
0,
96
0,
129,
36
#12
11
1
0
4
W5E1
0,
0,
96
-129,
0,
36
#12
11
1
0
5
W6E1
0,
0,
96
0,
-129,
36
#12
11
1
0
6
W1E1
0,
0,
96
129,
0,
36
#12
11
1
0
0,
0,
6
0,
0,
90
1
11
1
0
7
Total Segments: 77
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
% From E1
1
0.00
Actual Pos.
% From E1
4.55
No loads specified
No transmission lines specified
No transformers specified
No L Networks specified
166
Segs
Seg
1
Amplitude
(V/A)
1
Phase
Type
(deg.)
0
I
ANTENNAS FOR 100 POUND DXPEDITIONS
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.001
5
Height
R Coord.
(in)
(in)
0
0
The SWR plot for this antenna appears below.
Measurement not taken
SWR predicted by model
SWR measured by AntennaSmith
Figure 206 SWR for BP full-sized vertical with 4 radials on 10m at 8 feet
The far-field plot for this antenna over good ground appears below.
167
ANTENNAS FOR 100 POUND DXPEDITIONS
BP full-sized vertical on 15m with 4 radials
BP Full-sized vertical on 15m with 4 radials
Figure 207 BP full-sized vertical with 4 radials on 15m at 8 feet over good ground
The far-field plot for this antenna over poor ground appears below.
BP Full-sized vertical on 15m with 4 radials
BP Full-sized vertical on 15m with 4 radials
Figure 208 Buddipole full-sized vertical, 4 radials on 15m at 8 feet over poor ground
168
ANTENNAS FOR 100 POUND DXPEDITIONS
9.3.4 Buddipole full-sized vertical with 4 radials for 17m at 8 feet
The vertical for 17 meters appears below.
Figure 209 Buddipole full-sized vertical for 17m with 4 radials
Below is the model data for this antenna.
EZNEC+ ver. 5.0
BP long vert 4 rad 17m at 8ft
9/3/2007
10:09:13 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 18.1 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
Coord. (in)
X
Y
End 2
Z
1
W3E1
0,
0,
96
2
W1E2
0,
0,
139
Conn.
W2E1
Coord. (in)
Dia (in)
Segs
Z
Ins
X
Y
Diel C
Thk(in)
0,
0,
139
0.75
11
1
0
0,
0,
251
0.5
11
1
0
3
W4E1
0,
0,
96
0,
152,
36
#12
11
1
0
4
W5E1
0,
0,
96
-152,
0,
36
#12
11
1
0
5
W6E1
0,
0,
96
0,
-152,
36
#12
11
1
0
6
W1E1
0,
0,
96
152,
0,
36
#12
11
1
0
0,
0,
6
0,
0,
90
1
11
1
0
7
Total Segments: 77
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
% From E1
1
0.00
Actual Pos.
% From E1
4.55
Seg
1
Amplitude
(V/A)
1
Phase
Type
(deg.)
0
I
No loads specified
No transmission lines specified
No transformers specified
169
ANTENNAS FOR 100 POUND DXPEDITIONS
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
The SWR plot for this antenna appears below.
Measurement not taken
SWR predicted by model
SWR measured by AntennaSmith
Figure 210 SWR for BP full-sized vertical with 4 radials on 17m at 8 feet
The far-field plot for this antenna over good ground appears below.
170
ANTENNAS FOR 100 POUND DXPEDITIONS
BP full-sized vertical on 17m with 1 radial
BP Full-sized vertical on 17m with 1 radial
Figure 211 BP full-sized vertical with 4 radials on 10m at 8 feet over good ground
The far-field plot for this antenna over poor ground appears below.
BP Full-sized vertical on 17m with 4 radials
BP Full-sized vertical on 17m with 4 radials
Figure 212 Buddipole full-sized vertical, 4 radials on 17m at 8 feet over poor ground
171
ANTENNAS FOR 100 POUND DXPEDITIONS
9.3.5 Buddipole full-sized vertical with 4 radials for 20m at 8 feet
The vertical for 20 meters appears below.
Figure 213 Buddipole full-sized vertical for 20m with 4 radials
Below is the model data for this antenna.
EZNEC+ ver. 5.0
BP long vert 4 rad 20m at 8ft
9/3/2007
10:18:26 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 14 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES -------------No.
End 1
Conn.
Coord. (in)
End 2
X
Y
1
W3E1
0,
0,
96
2
W1E2
0,
0,
3
W4E1
0,
4
W5E1
5
W6E1
6
W1E1
7
Z
Conn.
Coord. (in)
Dia (in)
Z
Y
0,
0,
182
0.75
11
Diel C
1
0
182
0,
0,
294
0.5
11
1
0
0,
96
0,
198,
36
#12
11
1
0
0,
0,
96
-198,
0,
36
#12
11
1
0
0,
0,
96
0,
-198,
36
#12
11
1
0
0,
0,
96
198,
0,
36
#12
11
1
0
0,
0,
6
0,
0,
90
1
11
1
0
-------------- SOURCES -------------Specified Pos.
Wire #
1
% From E1
1
0.00
Actual Pos.
% From E1
4.55
No loads specified
No transmission lines specified
No transformers specified
172
Ins
X
W2E1
Total Segments: 77
No.
Segs
Seg
1
Amplitude
(V/A)
1
Phase
Type
(deg.)
0
I
Thk(in)
ANTENNAS FOR 100 POUND DXPEDITIONS
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
The SWR plot for this antenna appears below.
Measurement not taken
SWR predicted by model
SWR measured by AntennaSmith
Figure 214 SWR for BP full-sized vertical with 4 radials on 20m at 8 feet
The far-field plot for this antenna over good ground appears below.
173
ANTENNAS FOR 100 POUND DXPEDITIONS
BP full-sized vertical on 20m with 4 radials
BP Full-sized vertical on 20m with 4 radials
Figure 215 BP full-sized vertical with 4 radials on 20m at 8 feet over good ground
The far-field plot for this antenna over poor ground appears below.
BP Full-sized vertical on 20m with 4 radials
BP Full-sized vertical on 20m with 4 radials
Figure 216 Buddipole full-sized vertical, 4 radials on 20m at 8 feet over poor ground
174
ANTENNAS FOR 100 POUND DXPEDITIONS
9.4
Buddipole full-sized vertical with 1 radial at 16 feet
The single radial version of these antennas is now moved up to 16 feet. All radials now
descend at 45 degrees. We still have the bizarre patterns found at 8 feet.
9.4.1 Buddipole full-sized vertical with 1 radial for 10m at 16 feet
The vertical for 10 meters appears below.
Figure 217 Buddipole full-sized vertical for 10m with 1 radial
Below is the model data for this antenna.
EZNEC+ ver. 5.0
BP long vert 1 rad 10m at 16ft
9/2/2007
8:21:52 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 28.3 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Insulation
Conn.
1
W3E1
Coord. (in)
X
Y
0,
0,
End 2
Z
192
Conn.
W2E1
Coord. (in)
X
Y
0,
0,
Dia (in)
Z
214
Segs
Diel C
0.75
11
Thk(in)
1
0
2
W1E2
0,
0,
214
0,
0,
294
0.5
11
1
0
3
W1E1
0,
0,
192
0,
69,
119
0.5
11
1
0
0,
0,
6
0,
0,
186
1
11
1
0
4
Total Segments: 44
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
% From E1
1
0.00
Actual Pos.
% From E1
4.55
Seg
1
Amplitude
(V/A)
1
Phase
Type
(deg.)
0
I
No loads specified
175
ANTENNAS FOR 100 POUND DXPEDITIONS
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
The SWR plot for this antenna appears below.
SWR predicted by model
SWR measured by AntennaSmith
Figure 218 SWR for BP full-sized vertical with 1 radial on 10m at 16 feet
The far-field plot for this antenna over good ground appears below.
176
ANTENNAS FOR 100 POUND DXPEDITIONS
BP full-sized vertical on 10m with 1 radial
BP Full-sized vertical on 10m with 1 radial
Figure 219 BP full-sized vertical with 1 radial on 10m at 16 feet over good ground
The far-field plot for this antenna over poor ground appears below.
BP Full-sized vertical on 10m with 1 radial
BP Full-sized vertical on 10m with 1 radial
Figure 220 Buddipole full-sized vertical, 1 radial on 10m at 16 feet over poor ground
177
ANTENNAS FOR 100 POUND DXPEDITIONS
9.4.2 Buddipole full-sized vertical with 1 radial for 12m at 16 feet
The vertical for 12 meters appears below.
Figure 221 Buddipole full-sized vertical for 12m with 1 radial
Below is the model data for this antenna.
EZNEC+ ver. 5.0
BP long vert 1 rad 15m at 16ft
9/2/2007
8:42:23 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 24.9 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Coord. (in)
Conn.
X
Y
Z
End 2
Coord. (in)
Conn.
X
Y
Segs
Z
Diel C
Thk(in)
W3E1
0,
0,
192
0,
0,
214
0.75
11
1
0
2
W1E2
0,
0,
214
0,
0,
305
0.5
11
1
0
3
W1E1
0,
0,
192
0,
81,
110
0.5
11
1
0
0,
0,
6
0,
0,
186
1
11
1
0
Total Segments: 44
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
% From E1
1
0.00
Actual Pos.
% From E1
4.55
No loads specified
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
178
Ins
1
4
W2E1
Dia (in)
Seg
1
Amplitude
(V/A)
1
Phase
Type
(deg.)
0
I
ANTENNAS FOR 100 POUND DXPEDITIONS
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.001
5
Height
R Coord.
(in)
(in)
0
0
The SWR plot for this antenna appears below.
SWR predicted by model
SWR measured by AntennaSmith
Figure 222 SWR for BP full-sized vertical with 1 radial on 12m at 16 feet
The far-field plot for this antenna over good ground appears below.
179
ANTENNAS FOR 100 POUND DXPEDITIONS
BP full-sized vertical on 12m with 1 radial
BP Full-sized vertical on 12m with 1 radial
Figure 223 BP full-sized vertical with 1 radial on 12m at 16 feet over good ground
The far-field plot for this antenna over poor ground appears below.
BP Full-sized vertical on 12m with 1 radial
BP Full-sized vertical on 12m with 1 radial
Figure 224 Buddipole full-sized vertical, 1 radial on 12m at 16 feet over poor ground
180
ANTENNAS FOR 100 POUND DXPEDITIONS
9.4.3 Buddipole full-sized vertical with 1 radial for 15m at 16 feet
The vertical for 15 meters appears below.
Figure 225 Buddipole full-sized vertical for 15m with 1 radial
Below is the model data for this antenna.
EZNEC+ ver. 5.0
BP long vert 1 rad 15m at 16ft
9/2/2007
9:38:31 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 21.2 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Insulation
Conn.
Coord. (in)
X
Y
End 2
Z
Conn.
X
Y
Dia (in)
Z
Segs
Diel C
Thk(in)
1
W3E1
0,
0,
192
0,
0,
214
0.75
11
1
0
2
W1E2
0,
0,
214
0,
0,
326
0.5
11
1
0
3
W1E1
0,
0,
192
0,
95,
97
0.5
11
1
0
0,
0,
6
0,
0,
186
1
11
1
0
4
W2E1
Coord. (in)
Total Segments: 44
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
% From E1
1
0.00
Actual Pos.
% From E1
4.55
Seg
1
Amplitude
(V/A)
1
Phase
Type
(deg.)
0
I
No loads specified
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA ---------------
181
ANTENNAS FOR 100 POUND DXPEDITIONS
No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
The SWR plot for this antenna appears below.
SWR predicted by model
SWR measured by AntennaSmith
Figure 226 SWR for BP full-sized vertical with 1 radial on 10m at 16 feet
The far-field plot for this antenna over good ground appears below.
182
ANTENNAS FOR 100 POUND DXPEDITIONS
BP full-sized vertical on 15m with 1 radial
BP Full-sized vertical on 15m with 1 radial
Figure 227 BP full-sized vertical with 1 radial on 15m at 16 feet over good ground
The far-field plot for this antenna over poor ground appears below.
BP Full-sized vertical on 15m with 1 radial
BP Full-sized vertical on 15m with 1 radial
Figure 228 Buddipole full-sized vertical, 1 radial on 15m at 16 feet over poor ground
183
ANTENNAS FOR 100 POUND DXPEDITIONS
9.4.4 Buddipole full-sized vertical with 1 radial for 17m at 16 feet
The vertical for 17 meters appears below.
Figure 229 Buddipole full-sized vertical for 17m with 1 radial
Below is the model data for this antenna.
EZNEC+ ver. 5.0
BP long vert 1 rad 17m at 16ft
9/2/2007
9:13:45 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 18.1 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Insulation
Conn.
Coord. (in)
X
Y
End 2
Z
Conn.
Dia (in)
Z
X
Y
Diel C
Thk(in)
0,
0,
235
0.75
11
1
0
W3E1
0,
0,
192
2
W1E2
0,
0,
235
0,
0,
347
0.5
11
1
0
3
W1E1
0,
0,
192
0,
110,
82
0.5
11
1
0
0,
0,
6
0,
0,
186
1
11
1
0
Total Segments: 44
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
% From E1
1
0.00
Actual Pos.
% From E1
4.55
No loads specified
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
184
Segs
1
4
W2E1
Coord. (in)
Seg
1
Amplitude
(V/A)
1
Phase
Type
(deg.)
0
I
ANTENNAS FOR 100 POUND DXPEDITIONS
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
The SWR plot for this antenna appears below.
SWR predicted by model
SWR measured by AntennaSmith
Figure 230 SWR for BP full-sized vertical with 1 radial on 17m at 16 feet
The far-field plot for this antenna over good ground appears below.
185
ANTENNAS FOR 100 POUND DXPEDITIONS
BP full-sized vertical on 17m with 1 radial
BP Full-sized vertical on 17m with 1 radial
Figure 231 BP full-sized vertical with 1 radial on 10m at 16 feet over good ground
The far-field plot for this antenna over poor ground appears below.
BP Full-sized vertical on 17m with 1 radial
BP Full-sized vertical on 17m with 1 radial
Figure 232 Buddipole full-sized vertical, 1 radial on 17m at 16 feet over poor ground
186
ANTENNAS FOR 100 POUND DXPEDITIONS
9.4.5 Buddipole full-sized vertical with 1 radial for 20m at 16 feet
The vertical for 20 meters appears below.
Figure 233 Buddipole full-sized vertical for 20m with 1 radial
Below is the model data for this antenna.
EZNEC+ ver. 5.0
BP long vert 1 rad 20m at 16ft
9/2/2007
9:24:40 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 14 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Insulation
Conn.
Coord. (in)
X
Y
End 2
Z
Conn.
Dia (in)
Z
Segs
X
Y
Diel C
Thk(in)
0,
0,
278
0.75
11
1
0
1
W3E1
0,
0,
192
2
W1E2
0,
0,
278
0,
0,
390
0.5
11
1
0
3
W1E1
0,
0,
192
0,
147,
45
0.5
11
1
0
0,
0,
6
0,
0,
186
1
11
1
0
4
W2E1
Coord. (in)
Total Segments: 44
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
% From E1
1
0.00
Actual Pos.
% From E1
4.55
Seg
1
Amplitude
(V/A)
1
Phase
Type
(deg.)
0
I
No loads specified
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA ---------------
187
ANTENNAS FOR 100 POUND DXPEDITIONS
No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
The SWR plot for this antenna appears below.
SWR predicted by model
SWR measured by AntennaSmith
Figure 234 SWR for BP full-sized vertical with 1 radial on 20m at 16 feet
The far-field plot for this antenna over good ground appears below.
188
ANTENNAS FOR 100 POUND DXPEDITIONS
BP full-sized vertical on 20m with 1 radial
BP Full-sized vertical on 20m with 1 radial
Figure 235 BP full-sized vertical with 1 radial on 20m at 16 feet over good ground
The far-field plot for this antenna over poor ground appears below.
BP Full-sized vertical on 20m with 1 radial
BP Full-sized vertical on 20m with 1 radial
Figure 236 Buddipole full-sized vertical, 1 radial on 20m at 16 feet over poor ground
189
ANTENNAS FOR 100 POUND DXPEDITIONS
9.5
Buddipole comparisons and conclusions
9.5.1 Gain and take-off angles of configurations
Below is a table summarizing the gain and take-off angle for the Buddipole configurations
discussed above.
Buddipole Configuration Comparisons
Standard
BP
Standard
BP
Standard
BP
Long BP
Long BP
BP
Loaded
Vertical
Loaded
Vertical
Loaded
Vertical
Full-size
Vertical
Full-size
Vertical
dipole
L
L
1 radial
4 radials
1 radial
16 feet
@ 8 feet
@ 16 feet
16 feet
8 feet
16 feet
6.93 dBi
4.62 dBi
5.21 dBi
0.03 dBi
1.62 dBi
0.03 dBi
30 deg
30 deg
20 deg
15 deg
20 deg
15 deg
6.38 dBi
3.77 dBi
4.67 dBi
1.71 dBi
1.47 dBi
1.77 dBi
35 deg
30 deg
20 deg
20 deg
20 deg
15 deg
5.89 dBi
3.48 dBi
4.57 dBi
2.38 dBi
1.41 dBi
2.31 dBi
40 deg
40 deg
25 deg
20 deg
20 deg
20 deg
5.67 dBi
4.52 dBi
5.49 dBi
2.53 dBi
0.87 dBi
2.03 dBi
Standard
10m
10m
12m
12m
15m
15m
17m
17m
50 deg
50 deg
30 deg
20 deg
20 deg
25 deg
X
3.11 dBi
3.87 dBi
2.53 dBi
0.44 dBi
1.52 dBi
20m
20m
X
70 deg
40 deg
25 deg
20 deg
20 deg
Table 4 Buddipole gain and take-off angle summary
The dipole configurations have take-off angles too high for good DX. Further, they are
difficult to match over 15m. Neither of these facts should be surprising.
The “L” configuration has two problems: it is awkward on the top of the mast with the
weight significantly off-center, and it still has a very high take-off angle on 20m. The
numbers do indicate that there may be some value in having the radials level instead of
sloping, however.
The vertical configurations (loaded and unloaded) with a single radial provide low take-of
angles and an interesting pattern. A vertical cannot have gain in one direction without
190
ANTENNAS FOR 100 POUND DXPEDITIONS
sacrificing power in another and this is evident from the plots. Additional sloping radials
should smooth out the pattern while still retaining the low take-off angle.
9.5.2 Comparing Buddipole to Force-12 Sigma-5
This white paper began by analyzing the Force-12 Sigma-5. This section compares the fullsized vertical antenna built from the Buddipole at 8 feet with 4 radials. Both azimuth and
elevation plots for these antennas on the bands 10-20m appear below. The Force-12 Sigma-5
always appears on the left; the full-sized Buddipole vertical always appears on the right.
In comparing these antenna plots we should examine the maximum gain, directivity, deep
nulls in the patterns, and other aspects of the far field pattern. Since we are also doing this
analysis for 100 Pound DXpeditions we should consider the weight and packing size of
these antennas. (Also note that the Force-12 Sigma-5 is a multiple-band antenna reducing
the time we spend doing antenna erection and the amount of coax required for deploying
antennas for these five bands.)
The Buddipole deployed as a full-sized vertical with four sloping radials is about 1.5 dB
better than the Force-12 Sigma-5 antenna on all the bands. The Buddipole also has a slightly
lower take-off angle on each band. Putting these values in perspective, consider the power
difference as a percentage. If the difference between two powers is 1.5 dB then the ratio
between the two powers is:
X dB
% difference = 10
10
If system A is 1.5 dB less than system B, then system A is putting out 70% of the power of
system B. So, if we are putting out 100 watts in system B, we are only putting out 70 watts
in system A. Considering that a factor of 4 is an S-unit, this is something like a quarter of an
S-unit worth of difference. How much weight is this worth? How much space is this worth?
These are the kinds of tradeoffs that are considered during 100 Pound DXpedition planning.
The plots comparing these antennas appear below.
191
ANTENNAS FOR 100 POUND DXPEDITIONS
Force-12 Sigma-5 on 10m
BP Full-sized vertical on 10m with 4 radials
Figure 237 Force-12 Sigma-5 vs. BP full-sized vertical on 10m azimuth
Force-12 Sigma-5 on 10m
BP Full-sized vertical on 10m with 1 radial
Figure 238 Force-12 Sigma-5 vs. BP full-sized vertical on 10m elevation
192
ANTENNAS FOR 100 POUND DXPEDITIONS
Force-12 Sigma-5 on 12m
BP Full-sized vertical on 12m with 4 radials
Figure 239 Force-12 Sigma-5 vs. BP full-sized vertical on 12m azimuth
Force-12 Sigma-5 on 12m
BP Full-sized vertical on 12m with 4 radials
Figure 240 Force-12 Sigma-5 vs. BP full-sized vertical on 12m elevation
193
ANTENNAS FOR 100 POUND DXPEDITIONS
Force-12 Sigma-5 on 15m
BP Full-sized vertical on 15m with 4 radials
Figure 241 Force-12 Sigma-5 vs. BP full-sized vertical on 15m azimuth
Force-12 Sigma-5 on 15m
BP full-sized vertical on 15m with 1 radial
Figure 242 Force-12 Sigma-5 vs. BP full-sized vertical on 15m elevation
194
ANTENNAS FOR 100 POUND DXPEDITIONS
Force-12 Sigma-5 on 17m
BP Full-sized vertical on 17m with 4 radials
Figure 243 Force-12 Sigma-5 vs. BP full-sized vertical on 17m azimuth
Force-12 Sigma-5 on 17m
BP Full-sized vertical on 17m with 4 radials
Figure 244 Force-12 Sigma-5 vs. BP full-sized vertical on 17m elevation
195
ANTENNAS FOR 100 POUND DXPEDITIONS
Force-12 Sigma-5 on 20m
BP Full-sized vertical on 20m with 4 radials
Figure 245 Force-12 Sigma-5 vs. BP full-sized vertical on 20m azimuth
Force-12 Sigma-5 on 20m
BP Full-sized vertical on 20m with 4 radials
Figure 246 Force-12 Sigma-5 vs. BP full-sized vertical on 20m elevation
196
ANTENNAS FOR 100 POUND DXPEDITIONS
10 SMALL ANTENNAS 10-20M CONCLUSIONS
Antennas mounted on or near the ground which are relatively light and inconspicuous are
not going to have the same gain or pattern as a yagi at 70 feet. That said, the choices
explored in this white paper: the TW Antennas Traveler, Force-12 Sigma-5, quarter-wave
vertical with 16 radials, and full-sized Buddipole vertical, all offer relatively good
performance while conforming to the other constraints of weight and size. The figure below
arrays the four interesting configurations for 20 meters.
Antennas for 20m with elevation plots and relative power outputs
-1.99 dBi
-1.24 dBi
-0.05 dBi
0.44 dBi
30 degrees
25 degrees
25 degrees
20 degrees
57 watts
68 watts
89 watts
100 watts
TW Antennas
Traveler
Force-12 Sigma-5
Quarter-wave
vertical 16 radials
Buddipole full-sized
vertical with 4 radials
Figure 247 Comparing various 20m antenna options
The quarter-wave vertical falls below the Buddipole only because the feed point and radials
are closer to the ground. Modeling shows that lifting the quarter-wave vertical higher
provides similar characteristics to the Buddipole as specified. However, a 20-meter quarterwave vertical can be held up by a relatively inexpensive (and very lightweight) 20-foot
fishing pole. A 33-foot mast holding the antenna up high enough to equal the performance
of the Buddipole is significantly heavier and more costly than the fishing pole. For 0.5 dB it
probably isn’t worth it. Further, the quarter-wave vertical can be reduced to only 4 radials
and the gain drops to -0.11 dBi. So, a vastly simpler antenna system (with 12 fewer radials)
costs very little in performance.
The two compact vertical dipoles compare very well to the other full-sized antennas. Yes,
there is some drop in gain, but it is not an S-unit, or even half-an-S-unit (though we get close
to that on the TW Antennas Traveler). Concerns that these systems might be “elaborate
dummy loads” are unfounded. These antennas perform fairly well on 20m and even better
197
ANTENNAS FOR 100 POUND DXPEDITIONS
on the higher bands. Certainly, they perform well enough to merit further consideration for
inclusion in our kits.
The size, weight, and performance of the antenna is only part of the equation. Again, if we
were to deploy 5 single-band antennas the weight and space requirements for those items
would likely exceed that of a single mult-band antennas. Further, a multiband antenna
requires a single run of coax. Five 50-foot runs of RG-8X weighs 10 pounds. One 50-foot
run of RG-213 weighs under 6 pounds. Losses in the antenna system might be partially
offset by fewer losses in the feed line—all while meeting the same weight and space budget.
In this case, at 2:1 SWR and at 30 MHz, the loss of the very lightweight coax is about 1 dB
and the loss of the RG-213 is about half that (0.53 dB). It is important to evaluate whole
systems of things and not just component pieces.
The Buddipole Deluxe Package comes with two coils, two arms, two (short) whips, tripod,
and mast. If the intention is to only use this antenna on 20 meters and above, I would
recommend removing the coils from the package and replacing them with two additional
arms, two additional long whips (one as a spare), and enough wire to create four elevated
radials as described here. Perhaps Buddipole Antennas should sell such a configuration as
the “BuddiVert” or some similar name. The elevated full-sized quarter-wave vertical with
the large diameter element and elevated radials performs very well, is configurable for 5
bands, and should weigh-in at less than 9 pounds.
The two small vertical dipoles evaluated exceeded expectations. Though the performance
was below the various single-band antennas it was close enough to strongly consider
inclusion on a 100 Pound DXpedition because of the convenience of supporting 5 bands
with one unit, and the weight and space savings for having one radiator and one coax feed
for five bands. Perhaps the weight savings on these bands could allow bringing enough
materials to support another band like 80 meters. If the sacrifice of 1 dB on some bands
allowed operation on another band that would otherwise be unavailable, this seems like a
worthwhile trade-off. Again, with no weight or size limits we would not need to make such
compromises. But, this approach to DXpeditioning embraces cold calculations and giveand-take for all aspects of a portable station.
Discussions of these small antennas have largely ignored a major influence on their
performance: the effects of ground. This is addressed in the next chapter.
198
ANTENNAS FOR 100 POUND DXPEDITIONS
11 THE EFFECTS OF GROUND
The far field plots for the antennas discussed have been made over two specified types of
ground:
•
Good ground (0.005 S/m, dielectric constant 13)
•
Poor ground (0.001 S/m, dielectric constant 5)
These are but two of the infinite combinations of ground shapes and conductivity that may
appear under our antenna systems. There is a large range of ground types to consider from
“free space” (no ground) to a “perfect ground” that has infinite conductivity.
The effects of ground are best shown with far field plots. The two plots “good ground” and
“poor ground” tell only part of the story. What if we were to put the antenna on the beach
(over sand) but right on the ocean’s edge? What if we place the antenna over the end of a
dock on the ocean or a fresh water lake? How about mounting the antenna on the roof of a
high building? The following sections will investigate the effects of ground on various
antenna systems.
11.1 Long ground radials for the Force-12 Sigma-5
All of these situations will produce significantly different results than have been shown with
our “standard” two plots of “good” and “poor” ground. We will use the Force-12 Sigma-5
vertical dipole antenna on 20m for our examination of the effects of ground. After seeing
plots like the following, it is difficult not to change the way you look at the ground beneath
antennas.
199
ANTENNAS FOR 100 POUND DXPEDITIONS
Free space
High building
Poor ground
Sandy dry ground
Good ground
Rich soil
Fresh water
Salt water
Perfect ground
Force-12 Sigma-5 on 20m over various ground types
Figure 248 Force-12 Sigma-5 on 20m over a range of ground types
200
ANTENNAS FOR 100 POUND DXPEDITIONS
The antenna over perfect ground sends a good portion of its energy right down the surface of
the perfect ground. The take-off angle is even shown as zero degrees. The antenna
positioned on the surface of salt water does nearly as well. (Hence, the popular notion that
the best QTH is the mountain-top with a salt water pond on top.) Other grounds produce
increasing take-off angles and reduced gains.
An interesting exotic location may be on sandy and dry ground. What can be done that is
relatively easy and requires only lightweight materials to combat these losses to a poor
ground? Short of building a salt pond beneath the antenna extending several wavelengths,
the easiest way to combat this problem is with a ground wire system.
Assume the antenna is positioned over poor ground (0.001 S/m, dielectric constant 5).
Adding one wavelength wires on one inch above the ground in a radial pattern beneath the
antenna substantially reduces the ground loss. Note that these wires are not even connected
to the antenna! Consider the following far field plots with varying radial configurations.
No radials
8 radials
16 radials
-2.29 dBi
-0.81 dBi
0.88 dBi
Baseline over poor ground
1.48 dB better
3.17 dB better!
Force-12 Sigma-5 vertical dipole antenna on 20m above radial wires
Figure 249 Full-wave radials used to reduce ground loss
The 16 radial configuration doubles the effectiveness of the antenna system. It requires over
1100 feet of wire to complete the array (70 feet x 16 radials = 1120 feet) but the wire diameter
can be very small. AWG #26 wire was specified in the model. A spool of such wire weighs only
a couple of pounds. What other two pound accessory can you think of that would double the
effectiveness of your antenna system? The following plots show effects on the other bands.
201
ANTENNAS FOR 100 POUND DXPEDITIONS
Force-12 Sigma-5 on 10m no radials
Force-12 Sigma-5 on 10m with 16 radials
Figure 250 Force-12 Sigma-5 on 10m compares no radials and 16 radials
Force-12 Sigma-5 on 12m no radials
Force-12 Sigma-5 on 12m with 16 radials
Figure 251 Force-12 Sigma-5 on 12m compares no radials and 16 radials
202
ANTENNAS FOR 100 POUND DXPEDITIONS
Force-12 Sigma-5 on 15m no radials
Force-12 Sigma-5 on 15m with 16 radials
Figure 252 Force-12 Sigma-5 on 15m compares no radials and 16 radials
Force-12 Sigma-5 on 17m no radials
Force-12 Sigma-5 on 17m with 16 radials
Figure 253 Force-12 Sigma-5 on 17m compares no radials and 16 radials
203
ANTENNAS FOR 100 POUND DXPEDITIONS
A summary of the benefits of these 67 foot radials under this antenna is shown in the table
below:
Band
No radials
With 16 radials 67
feet long
10m
-0.45 dBi
1.08 dBi
1.53 dB
12m
-0.79 dBi
0.56 dBi
1.35 dB
15m
-1.20 dBi
1.07 dBi
2.27 dB
17m
-1.59 dBi
0.44 dBi
2.03 dB
20m
-2.29 dBi
0.88 dBi
3.17 dB
Difference
Table 5 Force-12 Sigma-5 gain comparisons 16 67-foot radials vs. no radials
The lower bands had fewer problems with the lossy ground so the radials were not as
important to their performance. But, the 20m configuration which had suffered considerably
from the poor ground picked up over 3 dB (as discussed). The fact that a single radial
system can be used to increase the performance of five bands is another argument for the
consideration of a multiband antenna like the Force-12 Sigma-5 or the TW Antennas 2010
Traveler.
How effective are these radials? The radials help produce results that exceed the rich soil
identified above and approach results obtained when positioned over fresh water. Again, it is
important to emphasize that we have not altered the antenna in any way; we have only
altered the environment in which the antenna operates.
11.2 The effects of radial length on a vertical dipole
The ARRL Antenna Book discusses extensively the effects of ground for a quarter wave
vertical antenna. This not what is under discussion here. The vertical dipole antenna behaves
differently than its quarter wave vertical monopole cousin. Therefore, advice given for the
quarter wave monopole cannot be directly applied here. For example, the advice to limit
radial length to 0.1 if there are 16 radials or fewer does not apply here. Consider the
following.
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ANTENNAS FOR 100 POUND DXPEDITIONS
Over 16 radials length 8 feet
Over 16 radials length 16
feet
Over 16 radials length 33
feet
Force-12 Sigma-5 on 20m
Figure 254 Varying radial lengths for 16 radials over a vertical dipole
Sixteen radials at varying lengths of 8, 16, and 33 feet provide the above results. Note that
the 33 foot radial set actually outperforms the 67 foot radial set described previously! (The
33 foot radials have 1.08 dBi of gain; the 67 foot radials have 0.89 dBi of gain.)
What happens if the number of radials is doubled? Consider the following with differing
lengths of 32 radials under a vertical dipole antenna in Figure 255. Doubling the number of
8 foot radials does nearly nothing to our gain (-2.14 dBi vs. -2.07 dBi). There is a very small
pickup in gain by doubling the number of 16 foot radials (-1.75 vs. -1.48). The 33 foot
radials (about a half-wavelength in length for 20m) also shows a very small pickup in gain
(1.08 dBi vs. 1.43 dBi).
Doubling the number of radials did very little to help the gain. Certainly, the time and effort
to lay 16 extra radials for a gain of about 0.3 dB seems wasted.
205
ANTENNAS FOR 100 POUND DXPEDITIONS
Over 32 radials length 8 feet
Over 32 radials length 16
feet
Over 32 radials length 33
feet
Force-12 Sigma-5 on 20m
Figure 255 Varying radial length for 32 radials over a vertical dipole
Computations were performed for the five bands over this new set of radials (16 by 33-feet)
which yielded the following new data.
Band
No radials
With 16 radials 33
feet long
Difference
10m
-0.45 dBi
1.49 dBi
1.94 dB
12m
-0.79 dBi
0.62 dBi
1.41 dB
15m
-1.20 dBi
-0.36 dBi
1.56 dB
17m
-1.59 dBi
0.06 dBi
1.65 dB
20m
-2.29 dBi
1.08 dBi
3.37 dB
Table 6 Force-12 Sigma-5 gain comparisons 16 33-foot radials vs. no radials
The numbers hint at something going on here other than a simple linear relationship between
gain and radial length. The table below shows data for radial lengths 8 feet through 48 feet
in roughly four-foot increments. The bands are arrayed in the vertical axis; the lengths of
each of the 16 radials is shown in the horizontal axis.
206
ANTENNAS FOR 100 POUND DXPEDITIONS
10
12
15
17
20
-0.45
-0.78
-1.20
-1.59
-2.29
0
0.23
-0.66
-1.09
-1.48
-2.14
8
0.55
-0.32
-0.87
-1.30
-1.97
12
1.43
0.75
-0.25
-1.30
-1.75
16
0.70
1.21
1.08
-0.07
-1.39
20
0.43
0.16
1.03
1.17
-0.68
24
0.92
-0.35
0.13
0.95
0.53
28
1.49
0.62
-0.36
0.06
1.08
33
1.04
1.68
-0.20
-0.25
0.68
36
0.85
1.38
0.93
-0.38
0.12
40
1.14
0.58
1.63
0.07
-0.22
44
1.37
0.23
1.06
1.13
-0.37
48
Table 7 Force-12 Sigma-5 computed gains with 16 radials of varying length
The table below has gains relative to the antenna over no radials. The two highest gain
values for each band are shown in bold.
10m
12m
15m
17m
20m
0.00
0.00
0.00
0.00
0.00
0
0.68
0.12
0.11
0.11
0.15
8
1.00
0.46
0.11
0.29
0.32
12
1.88
1.53
-0.25
0.29
0.54
16
1.15
1.99
1.08
1.52
0.90
20
0.88
0.94
1.03
2.76
1.61
24
1.37
0.43
0.13
2.54
2.82
28
1.94
1.40
-0.36
1.65
3.37
33
1.49
2.46
-0.20
1.34
2.97
36
1.30
2.16
0.93
1.21
2.41
40
1.59
1.36
1.63
1.66
2.07
44
Table 8 Relative gain (dB) of Force-12 Sigma-5 over 16 radials of various lengths
The numbers appear to be cyclic in the table and a graphing of those values confirms that
pattern. The graph below shows this relationship.
207
1.82
1.01
1.06
2.72
1.92
48
ANTENNAS FOR 100 POUND DXPEDITIONS
Figure 256 Radial length vs. gain for 16 radials under a Force-12 Sigma-5
Multiples of half-wave lengths per band appear to be the most effective. For 10m the lengths
16 feet, 33 feet, and 48 feet all have high gains and are multiples of a half-wave length. For
12m the lengths 19 feet and roughly 38 feet have good gains. For 15m radial lengths of 22
feet and 44 feet, which are also multiples of half-wave lengths, have good gain. The pattern
appears to hold for 17m and 20m as well.
11.3 Dual-length radials
The alternative to single-length radials is to use two (or more) differing lengths of radials
within the system. This section discusses using two lengths. Results from the above indicate
that 24-foot radials provide good performance on bands 15m and 17m, while 33-foot radials
provide good gain on 10m and 20m. Choosing these two radial lengths means only 12m was
forced to compromise (with the anticipated gain now only 0.94 instead of 1.99 as would be
yielded from a 20-foot radial). The models below show the effects of this two radial-length
system. We have eight radials at 33 feet and 8 others at 20 feet. All radials are evenly spaced
with the shorter radials interspersed with the longer ones.
208
ANTENNAS FOR 100 POUND DXPEDITIONS
Figure 257 16 radials alternating lengths of 20 feet and 33 feet under Force-12 Sigma-5
The comparisons between this configuration and the configuration previously described with
16 uniform length 33 foot radials should acknowledge that shortening half of the long
radials to only 20 feet will likely reduce the gain on the 20 meter band. Indeed, this is the
case as evidenced by the table below.
Band
10
12
15
17
20
No radials
-0.45
-0.78
-1.20
-1.59
-2.29
With 8@20-feet + 8@33 feet
Gain
Relative gain
+0.98
+1.22
-0.38
+0.87
-0.85
+1.43
+2.00
+0.82
+2.46
+1.44
With 16@33-feet
Relative Gain
Comparing
both
relative gains
+1.94
+1.40
-0.36
+1.65
+3.37
+0.51
-0.60
-1.18
-0.81
+1.93
Table 9 Comparing gains for the 16@33-feet and 8@20-feet + 8@33-feet
configurations
Nearly 2 dB was lost on 20m by shortening half of these radials. So, if the purpose of the
exercise was to pump up 20m then this is clearly an inferior solution to the 16 full-sized 33foot radials. But, the pickup of gain on 12m, 15m, and 17m is interesting—especially since
the new configuration uses much less wire (104 feet less).
The model for this configuration appears below (for the Force-12 Sigma-5 on 20m).
209
ANTENNAS FOR 100 POUND DXPEDITIONS
EZNEC+ ver. 5.0
Force-12 Sigma-5~20m 16x33+20
9/13/2007
9:16:22 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 14.2 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Insulation
Conn.
Thk(in)
1
W4E1
Coord. (in)
X
Y
0,
0,
Z
Conn.
29
W2E1
End 2
Coord. (in)
X
Y
0,
0,
Dia (in)
Segs
Z
Diel C
35
0.5
6
1
0
2
W1E2
0,
0,
35
W3E1
0,
0,
126
1
22
1
0
3
W2E2
0,
0,
126
W6E1
0,
0,
132
0.5
6
1
0
4
W5E1
0,
0,
29
0,
-24,
29
0.5
6
1
0
5
W1E1
0,
0,
29
0,
24,
29
0.5
6
1
0
6
W7E1
0,
0,
132
0,
-24,
132
0.5
6
1
0
7
W3E2
0,
0,
132
0,
24,
132
0.5
6
1
0
8
W9E1
0,
0,
1
0,
396,
1
#26
40
1
0
9
W10E1
0,
0,
1
-280.01,280.014,
1
#26
40
1
0
10
W11E1
0,
0,
1
0,
1
#26
40
1
0
11
W12E1
0,
0,
1
-280.01,-280.01,
1
#26
40
1
0
12
W13E1
0,
0,
1
-396,
1
#26
40
1
0
13
W14E1
0,
0,
1
280.014,-280.01,
1
#26
40
1
0
14
W15E1
0,
0,
1
0,
1
#26
40
1
0
15
W16E1
0,
0,
1
280.014,280.014,
1
#26
40
1
0
16
W17E1
0,
0,
1
222,
1
#26
40
1
0
17
W18E1
0,
0,
1
-91.924,222.032,
1
#26
40
1
0
18
W19E1
0,
0,
1
1
#26
40
1
0
19
W20E1
0,
0,
1
20
W21E1
0,
0,
1
21
W22E1
0,
0,
1
22
W23E1
0,
0,
1
23
W8E1
0,
0,
1
-396,
0,
396,
92,
-222,
92,
-222.03,-91.924,
1
#26
40
1
0
-222,
1
#26
40
1
0
91.924,-222.03,
1
#26
40
1
0
-92,
1
#26
40
1
0
222.032,91.9239,
1
#26
40
1
0
-92,
222,
Total Segments: 698
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
2
Actual Pos.
% From E1
% From E1
50.00
52.27
Amplitude
Phase
(V/A)
(deg.)
Seg
12
1
Type
0
I
-------------- LOADS (RLC Type) --------------
No.
Specified Pos.
Wire #
1
210
2
Actual Pos.
% From E1
% From E1
47.00
47.73
Seg
11
R
(ohms)
Open
L
(uH)
3.42
C
R Freq
(pF)
(MHz)
2
14.2
Type
Par
ANTENNAS FOR 100 POUND DXPEDITIONS
2
2
55.00
56.82
13
Open
3.42
2
14.2
Par
3
2
50.00
52.27
12
Short
0.52
Short
0
Ser
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.001
5
Height
R Coord.
(in)
(in)
0
0
An alternative configuration would be 8 radials at 33 feet and 8 radials at 24 feet. The gain
results for that configuration appear below.
Band
10
12
15
17
20
No radials
-0.45
-0.78
-1.20
-1.59
-2.29
With 8@24-feet + 8@33
feet
Gain
Relative gain
+0.79
+0.57
-0.20
+0.50
+0.43
+1.24
+1.35
+1.00
+2.09
+2.72
With 16@33-feet
Relative Gain
Comparing
both
relative gains
+1.94
+1.40
-0.36
+1.65
+3.37
+0.70
+0.05
-1.36
-0.44
+0.65
Table 10 Comparing gains for the 16@33-feet and 8@24-feet + 8@33-feet
configurations
There are minor reductions in gain compared to the 33-feet+20-feet radial pattern above on
10m (0.19 dB), 12m (0.65 dB), and 17m (0.38 dB). Gains relative to the other configuration
are found on 15m (0.18 dB), and 20m (1.28 dB). This new configuration still suffers on 10m
and 20m compared to the 16 radials of 33 feet, but shows better performance on all other
bands.
Returning to the comparison with the original baseline, the antenna situated over very poor
ground, the relative gains with these radials are somewhere between 1 dB for 15m to 2.72
dB for 20m. Again, this is achieved with less than 500 feet of very light wire. The question
is posed again: what other mechanism increases the performance of an antenna system on
five bands yet weighs under a pound?
Adding radials beneath the Force-12 Sigma-5 brings its performance to near parity with the
Buddipole vertical with four elevated radials. In fact, radial lengths can be selected which
would provide performance from this vertical dipole exceeding that of the Buddipole.
Ground-mounted radials are easier to install (though there are more of them) since we do not
need to rig a system to elevate them. Finally, we get all the flexibility and coax weight
savings of the multiple band antenna with this arrangement. If space is available to lay out
these radials, a multi-band vertical dipole with radials is a strong contender.
211
ANTENNAS FOR 100 POUND DXPEDITIONS
12 BALCONY ANTENNAS
12.1 Problem description
Not every evening will be spent in a spacious villa isolated on some island paradise. Some
evenings will be spent in a small hotel room. If you’re lucky, you might have a balcony a
little larger than a postage stamp from which you can deploy an antenna. This chapter will
discuss some options for this situation: operating from a high balcony.
There are a number of problems with such a venue. First, the balcony is likely to be very
small, which limits the kinds of things that can be deployed. Secondly, any antenna we
attempt to deploy will be very close to the building and very far from the ground. Finally,
except perhaps for the railing on the balcony, there are few places to attach or anchor
antenna pieces.
I would be remiss if I didn’t mention one of the most important things about balcony
antennas: safety. Dropping even a small item from a balcony on to an unsuspecting person at
ground level can result in serious injury or death. Please secure all items when deploying an
antenna system on a balcony. I routinely tie short lengths of Dacron rope to pieces to be sure
that anything that breaks loose (or simply breaks) will not fall to the ground.
Finally, the models included in these discussions will not consider the largest and most
influential items in our antenna system. The building with its bricks, concrete, rebar, and
stone will be ignored. Plots for far field energy distribution will therefore be absolutely bestcase. Results are likely to be much worse.
These antennas do not perform well. How can they?! They are probably shortened vertical
variants with poor radial systems positioned next to large building that will have detrimental
affects on the pattern and overall efficiency. But, even a poor antenna radiates some signal,
and some is better than none. I’ve made many contacts using a balcony antenna and had a
great deal of fun doing it.
12.2 20 meters
It is unlikely that you will be making 160m or 80m contacts from a balcony antenna. But,
40m, 30m, and 20m systems are possible with a minimum of fuss. This section discusses
some 20m antenna ideas.
12.2.1 Fishing pole horizontal antenna
As with any of these antennas, the main problem is to get the main radiator away from the
building and into free space as much as possible. The three general approaches for this are to
have a pole or mast extend a wire away from the building, use a mast such as that which
comes with a Deluxe Buddipole system to move the antenna and feed point away from the
building, or simply attach a radiator directly to the railing of the balcony. The antenna
discussed here uses a small collapsible fishing pole to hold a wire.
212
ANTENNAS FOR 100 POUND DXPEDITIONS
A Cabela’s Telescopic Panfish Pole (CP-14) is a 14 foot lightweight pole that collapses
down to 15.5 inches. It weighs just a few ounces. It is small enough that it can be packed
into a suitcase or briefcase along with the wire it supports.
Figure 258 Cabela’s 14 foot collapsible panfish pole
The general idea for this antenna design is to use this pole to route the main radiating wire
out from the balcony for up to 12 feet (leaving the first 2 feet of the pole on the balcony to
secure it). The remaining wire for the radiator will droop down off the end of the pole.
The small balcony prevents an elaborate radial system. Instead, a single wire is dropped
from the feed point straight down, and two other wires are routed around the periphery of
the balcony. The antenna view below illustrates this arrangement.
213
ANTENNAS FOR 100 POUND DXPEDITIONS
Figure 259 Balcony fishing pole antenna for 20m
The model for this antenna appears below.
EZNEC+ ver. 5.0
Balcony fishing pole 20m
9/14/2007
8:01:14 PM
--------------- ANTENNA DESCRIPTION --------------Frequency = 14.1 MHz
Wire Loss: Copper -- Resistivity = 1.74E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
214
X
Coord. (in)
Y
End 2
Z
Conn.
W2E1
X
Coord. (in)
Y
Dia (in)
Z
Segs
Diel C
Ins
Thk(in)
1
W3E1
0,
0,
2000
0,
120,
2000
#16
6
1
0
2
W1E2
0,
120,
2000
0,
120,
1910
#16
6
1
0
3
W7E1
0,
0,
2000
W4E1 -60,
0,
2000
#16
6
1
0
4
W3E2 -60,
0,
2000
W5E1 -60,
-60,
2000
#16
6
1
0
5
W4E2 -60,
-60,
2000
W6E1 -10,
-60,
2000
#16
6
1
0
6
W5E2 -10,
-60,
2000
-10,
-30,
2000
#16
6
1
0
7
W11E1
0,
0,
2000
W8E1
60,
0,
2000
#16
6
1
0
8
W7E2
60,
0,
2000
W9E1
60,
-60,
2000
#16
6
1
0
9
W8E2
60,
-60,
2000
W10E1
10,
-60,
2000
#16
6
1
0
10
W9E2
10,
-60,
2000
10,
-30,
2000
#16
6
1
0
11
W1E1
0,
0,
2000
0,
0,
1790
#16
6
1
0
ANTENNAS FOR 100 POUND DXPEDITIONS
Total Segments: 66
-------------- SOURCES -------------No.
Specified Pos.
Wire #
1
% From E1
1
Actual Pos.
% From E1
0.00
8.33
Amplitude
Seg
(V/A)
1
1
Phase
Type
(deg.)
0
I
No loads specified
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA ---------------
No.
Cond.
Diel. Const.
(S/m)
1
0.001
3
Height
R Coord.
(in)
(in)
0
0
The SWR for this antenna can be reasonable assuming that the main radiator is not being
detuned by the graphite pole. Lengthening or shortening the dropped (vertical) radial can
usually bring the antenna into tune.
Figure 260 SWR for 20m fishing pole balcony antenna
The far field plot for this antenna appears below. Again, the effects of the building are not
represented so at least half of the far field (that faces the building) will not be accurate.
215
ANTENNAS FOR 100 POUND DXPEDITIONS
20m fishing pole balcony antenna
20m fishing pole balcony antenna
Figure 261 20m fishing pole balcony antenna 2D far field pattern
The 3D far field plot appears below. The ridges appearing in the elevation plot above are
vivid in the 3D plot.
Figure 262 20m fishing pole balcony antenna 3D far field pattern
216
ANTENNAS FOR 100 POUND DXPEDITIONS
13 ANTENNAS FOR 6M
Though most DX work will be done on HF, the Magic Band can also bring some joy. This
chapter explores some small, easy to pack alternatives for the 6m band.
13.1 Hentenna from the Buddipole Users Group
The 6m Hentenna appeared on the Buddipole Users Group Yahoo! group in September of
20007. It was introduced by Katsuya Okamura (JE3NJZ/KH2E) and Takashi Kaida
(JE1HJA/N3JZ). The design uses standard Buddipole parts including
•
A center Tee such as the VersaTee
•
Two 22 inch arms
•
Two stainless steel whips (5.5 feet)
•
Two long whips (9.3 feet)
•
Two “IT” adapters (available from Buddipole Antennas)
•
Two knobs from a rotating arm kit (available from Buddipole Antennas)
Additionally, two 100 cm (39.4 inch) wire “jumpers” with gripping clips are used to
complete elements 4 and 7 shown in Figure 263. The entire antenna can be put on top of a
standard Buddipole tripod and mast system. The model for this antenna assumes usage of
the 16 foot mast.
The antenna is fed directly to the center Tee with 50 ohms. No special impedance matching
or loading were included in the model. The schematic view of this antenna appears below.
Figure 263 Hentenna for 6m antenna view
The SWR curve for this antenna over the entire 6m band is shown below.
217
ANTENNAS FOR 100 POUND DXPEDITIONS
Figure 264 Hentenna for 6m SWR
As the SWR curve shows, this antenna provides a good match for most of the 6m band.
The EZNEC model data for this antenna follows.
EZNEC+ ver. 5.0
Hentenna from BUG
9/14/2007
12:43:38 AM
--------------- ANTENNA DESCRIPTION --------------Frequency = 50.0 MHz
Wire Loss: Aluminum (6061-T6) -- Resistivity = 4E-08 ohm-m, Rel. Perm. = 1
--------------- WIRES --------------No.
End 1
Conn.
Coord. (in)
X
Y
End 2
Z
Ins
X
Y
0,
192
W3E1
22,
0,
192
0.75
11
Diel C
1
0
2
W5E1 -22,
0,
192
W4E1 -19.7,
0,
141
0.5
11
1
0
3
W6E1
0,
192
W4E2
19.7,
0,
141
0.5
11
1
0
4
W2E2 -19.7,
0,
141
W3E2
19.7,
0,
141
#16
11
1
0
5
W1E1 -22,
0,
192
W7E1
-22,
0, 270.75
0.5
11
1
0
6
W1E2
0,
192
W7E2
22,
0, 270.75
0.5
11
1
0
7
W5E2 -22,
0, 270.75
W6E2
22,
0, 270.75
#16
11
1
0
Total Segments: 77
-------------- SOURCES -------------No.
Specified Pos.
Wire #
218
Segs
W2E1 -22,
22,
Conn.
Dia (in)
1
22,
Z
Coord. (in)
% From E1
Actual Pos.
% From E1
Seg
Amplitude
(V/A)
Phase
(deg.)
Type
Thk(in)
ANTENNAS FOR 100 POUND DXPEDITIONS
1
1
50.00
50.00
6
1
0
I
No loads specified
No transmission lines specified
No transformers specified
No L Networks specified
Ground type is Real, High-Accuracy
--------------- MEDIA --------------No.
Cond.
Diel. Const.
(S/m)
1
0.005
13
Height
R Coord.
(in)
(in)
0
0
This antenna produces a pattern of good gain at a reasonably low angle of radiation
broadside to the antenna as illustrated in the three-dimensional Far Field plot shown below.
Figure 265 6m Hentenna Far Field Plot (3D)
The 2D far field plots for this antenna appear in the figure below.
219
ANTENNAS FOR 100 POUND DXPEDITIONS
Hentenna from Buddipole parts for 6m
Hentenna from Buddipole parts for 6m
Figure 266 Hentenna for 6m Far Field Plot over good ground
This antenna is light, provides 10 dBi of gain, and has a nice symmetrical pattern that would
make the antenna easy to aim in the field. Because the antenna is made from Buddipole parts,
one could construct this antenna or an afternoon or a day and then convert it back to HF use for
more traditional DXpeditioning work. Though it is also possible to make a Yagi from the
Buddipole parts, this antenna configuration is worth a try.
220
ANTENNAS FOR 100 POUND DXPEDITIONS
14 FINAL COMMENTS TO VOLUME 1
This white paper discussed a small number of antennas and antenna configurations that can
be created from simple materials or from popular commercial offerings. There is a great deal
of lore and superstition surrounding antennas within the amateur radio circles. Some of these
tales provide useful guidance; others are nonsensical. Sorting them out may not be easy but
it is well worth one’s time to try. This white paper is a small step towards that goal.
I owned the Force-12 Sigma-5 for several years. I sold it in the Spring of 2008 because it did
not travel as well as I had hoped it might. I suspect the ham that bought it is putting it to
good use in some semi-permanent installation. I note here that Force-12 (the company) has
been purchased and the new owner seems keen to revamp the product line, increase quality,
and streamline customer service. Force-12 antennas have a history of helping make
DXpeditions successful. It is a company worth watching.
I have purchased the TW Antennas TW2010 antenna system. This system has a very rugged
carry bag that holds the antenna components, controller cable, 50 feet of coax, the controller
box, and other small items. The X-base can ride on top of the bag, though it adds
considerable weight. Though the analysis here shows the antenna to be slightly inferior in
performance to the Sigma-5, it is much more rugged, breaks down smaller, packs easily, and
has a much more polished look and feel. With a suitable wire ground system as described in
this white paper, this could be a very good performer on a DXpedition—even over poor
ground.
I have deployed fishing pole vertical antennas with two or four elevated radials for band 80meters, 40-meters (which doubles as a nice 15-meter antenna), 20-meters, and 17-meters.
These antennas consist of little more than a fishing pole, center insulator, and wires.
Assembly at the DXpedition site is little more than unwinding the wires, taping the vertical
section (and its Dacron rope leader) to the top of a fishing pole, standing the fishing pole up
and lashing it to a fence post or small tree (or guying it), and stretching out the elevated
radials. These antennas, especially the 80-meter and 40-meter versions, can be deployed off
a second, third, or even fourth floor roof area to get the antenna well in the clear and the
radials high off the ground. These antennas perform very well and weigh next to nothing.
Though low-band antennas are out of the scope of this white paper, I will recommend this
approach here.
The Buddipole antenna systems perform very well as evidenced by this analysis. And, while
the dipole configuration was disparaged in the initial discussions, that configuration can be
very effective if deployed high above the ground. If, say, a 16 foot mast is extended above a
roofline 30 feet high, then the antenna is now at 46 feet—a big difference from the 16 foot
levels discussed here. As usual, anything written in a book or white paper like this must be
used within the context of its discussion. Just because a Buddipole dipole will not perform
well at 8 feet does not mean that a similarly configured system will not perform extremely
well if somehow deployed in the clear at a much greater height. How much better? Anyone
with access to EZNEC or other modeling programs can use the models supplied with this
white paper to make that determination. Feel free to use, edit, and explore the model data
presented here to learn more about these antenna systems in situations not explored here.
221
ANTENNAS FOR 100 POUND DXPEDITIONS
Weight, bulk, and length affect the ability to transport equipment for 100 Pound
DXpeditions. When investigating options for antennas always keep in mind that the
components must eventually fit into either a regular checked bag, or a hard-sided golf bag if
it is to travel on a commercial airliner. The Sigma-5 antenna did not have a carry case
available for it when I purchased the unit. Further, I never found a case suitable for its
oddly-shaped pieces. This is the primary reason why that antenna was sold.
The TW Antennas TW2010 does have a case available that is both rugged and roomy—
accommodating everything needed for the deployment of the antenna except the base. This
make the antenna attractive for this purpose.
The Buddipole systems also have cases available. Three different sizes of cases can be
obtained from Buddipole antennas: a small rectangular case for the mini-Buddipole or
Buddistick, a short case (about two feet long), and a long case (about four feet long). The
rectangular case and short case can fit easily into a regular checked bag; the long case drops
into a hard-sided golf bag easily.
Many of the interesting places to go have very poor ground beneath them. Hawaii, barrier
islands around the US, and the islands of the Caribbean all have this issue in common.
While advertised specifications for an antenna may make it look like a solid performer, it is
best to do your own analysis and model the unit over very poor ground to see what effect, if
any, this ground may have. It doesn’t matter if the antenna performs extremely well over salt
water if your operating location is over dry sand.
Finally, though many of these destinations are barren and have few high structures that can
be utilized for antenna supports, there are exceptions. If the property you are using has a
high balcony then use it. If there are trees present, consider stringing a wire antenna. Though
many times you will be the tallest thing in the vicinity, it will not always be so. Leverage
roof lines, trees, high decks and verandas, and any other on-site resources available.
Remember: higher is typically better than lower, and in the clear is better than in the clutter.
I hope that this will be the first of many such investigations. And, I hope that anyone who
reads this finds at least some of it useful or interesting. See you on the bands. 73!
Scott (NE1RD)
222
ANTENNAS FOR 100 POUND DXPEDITIONS
APPENDIX A BUDDIPOLE COIL INDUCTANCES
Turn
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
X(L)
0.07
0.27
0.55
0.89
1.29
1.72
2.19
2.68
3.20
3.73
4.28
4.84
5.41
5.99
6.57
7.17
7.77
8.38
8.99
9.61
Turn
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
X(L)
10.23
10.85
11.48
12.11
12.75
13.38
14.02
14.66
15.30
15.94
16.59
17.24
17.89
18.53
19.19
19.84
20.49
21.14
21.80
22.45
223
ANTENNAS FOR 100 POUND DXPEDITIONS
BUDDIPOLE LOW BAND COILS
Turn
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
224
X(L)
0.11
0.45
1.02
1.81
2.83
4.07
5.54
7.24
9.16
11.31
13.69
16.29
19.12
22.17
25.45
28.96
32.69
36.65
40.84
45.25
49.89
54.75
59.84
65.16
70.71
76.47
Turn
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
X(L)
82.47
88.69
95.14
101.82
108.72
115.84
123.20
130.78
138.58
146.61
154.87
163.36
172.07
181.01
190.17
199.56
209.17
219.02
229.09
239.38
249.90
260.65
271.62
282.82
294.25
305.90
ANTENNAS FOR 100 POUND DXPEDITIONS
REFERENCES
ARRL. More Wire Antenna Classics. American Radio Relay League, 2002.
Buddipole Users Group (BUG), http://groups.yahoo.com/group/buddipole
Cain, James D. Yasme: The Danny Weil and Colvin Radio Expeditions. American
Radio Relay League (ARRL), 2003.
Cebik, L. B. Arrl Antenna Modeling Course. Newington, CT: American Radio Relay
League, 2002.
Christman, Al. "A Study of Elevated Radial Ground Systems for Vertical Antennas (Part
1)." The National Contest Journal Vol 33 No 1 (2005): 19-22.
Christman, Al. "Compact Four-Squares." The National Contest Journal Vol 32 No 4
(2004): 10-12.
Christman, Al. "Verticals By the Sea." The National Contest Journal Vol 33 No 4 (2005):
9-12.
Christman, Al. "A Study of Elevated-Radial Ground Systems for Vertical Antennas (Part
2)." The National Contest Journal Vol 33 No 2 (2005): 17-20.
Christman, Al. "Verticals By the Sea (Part 2)." The National Contest Journal Vol 33 No
5 (2005): 4-6.
Devoldere, John. Arrl ON4UN's Low Band Dxing. American Radio Relay League
(ARRL), 2005.
Heyerdahl, Thor. Kon-Tiki: Across the Pacific in a Raft. Pocket, 1990.
Heys, John D. Practical Wire Antennas. Radio Society of Great Britain, 1989.
Kleinschmidt, Kirk A. Stealth Amateur Radio: Operate From Anywhere. AARL, 1999.
McCoy, Lew. Lew Mccoy on Antennas. Hicksville, New York: CQ Communications, Inc,
1994.
Morin, Jodi. ARRLs Wire Antenna Classics. Amer Radio Relay League, 1999.
Moxon, L.A. HF Antennas for All Locations. Amer Radio Relay League, 1993.
Orr, WIlliam I. The W6SAI HF Antenna Handbook. Hicksville, NY: CQ Communications,
Inc, 1996.
ARRL's Vertical Antenna Classics. Edited by Bob Schetgen. American Radio Relay
League (ARRL), 1995.
Sevick, Jerry. Transmission Line Transformers. Raleigh, NC: Scitech Publishing, Inc,
2001.
Sevick, Jerry. The Short Vertical Antenna and Ground Radial. Hicksville, NY: CQ
Communications, Inc, 2003.
Sterba, Kurt N. Aerials II. Worldradio, Inc, 1993.
The ARRL Antenna Book 21st Edition. Edited by R. Dean Straw. Newington, CT:
American Radio Relay League (ARRL), 2007.
Sturba, Kurt N. "Radial Question." WorldRadio Year 36 No 10 (2007): 52.
Sturba, Kurt N. "Radiation Resistance." WorldRadio Year 37 No 1 (2007): 49.
Sturba, Kurt N. "Short Vertical." WorldRadio Year 36 No 5 (2006): 52.
225
ANTENNAS FOR 100 POUND DXPEDITIONS
Sturba, Kurt N. "Efficiency." WorldRadio Year 37, Issue 3 (2007): 52.
The ARRL Handbook. Edited by Mark J. Wilson. Newington, CT: American Radio Relay
League (ARRL), 2006.
Additional resources were helpful in the construction of this work including:
•
Images from the http://www.timewave.com web site for the AntennaSmith device
and plots created with the device. Those images are used without permission.
•
Cabelas (http://www.cabelas.com) sells inexpensive Black Widow fishing poles used
on 100 Pound DXpeditions for vertical antennas and balcony radiators.
•
The Team Vertical story (http://www.k2kw.com/tv.html) provided some of the
impetus for the significant research done for this paper.
•
The Microlite Penguin DXpedition team led by DX legends like Bob Alphin
(K4UEE) often used half-wave vertical dipoles. A great deal can be learned by
watching the DXpedition videos available from Bob Alphin (http://www.k4uee.com)
or through DXvideos.com (http://www.dxvideos.com).
•
This work would not have been possible without a program such as EZNEC version
5.0 by Roy W. Lewallen. Version 5.0.7 of EZNEC+ was used for all antenna
modeling work. More information about this product is available from
http://www.eznec.com
•
Many ham radio products have on-line communities supporting them. The Buddipole
has the Yahoo! group http://groups.yahoo.com/group/Buddipole which has over
3000 members.
This white paper covers only a fraction of the antennas investigated on 100 Pound
Dxpeditions. More information about the 100 Pound DXpedition and works like this will
be made available on NE1RD’s home page http://www.bsandersen.com .
Change log
1.00 1.01: Wire diameter comparisons in section 6.4 had the formula for wire
circumfrence goofed up (dividing the diameter by 2 when that was unnecessary). In
section 9.5.2 the sentence “So, if we are putting out 100 watts in system B, we are only
putting out 70 watts in system B.” should read “So, if we are putting out 100 watts in
system B, we are only putting out 70 watts in system A.” (and now does).
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