Communication systems
 Terrestrial (VHF & HF) Marine Radios
 Satellite Services
 Cellular Networks
Strengths of a common distress channel
 Common channel for all vessels whether commercial or recreational.
 Distress calls go out as a broadcast to many stations rather than to an
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individual – as in the case when using a Cellphone.
Distress/Urgency calls are not reliant on a Coast station hearing the call
but can be answered and relayed by any station within VHF range of
the distress vessel.
Is recognised by international and domestic mariners as a common
channel, so no need to know what local channels (which vary region by
region) are.
The loss of a coast station receiver does not remove all assets from the
radio coverage area. i.e. other vessels can still hear each other.
Does not rely on repeaters and thus removes the single point of failure.
i.e. if a repeater fails that particular channel is rendered ineffective.
High Frequency
2182 kHz
•4125 kHz
•6215 kHz
•8291 kHz
•12290 kHz
•16420 kHz
•
Plus HF DSC
Satellite Communications
 Inmarsat
 Iridium
 Globalstar
Inmarsat
Only GMDSS approved satellite
system.
Inmarsat – B (voice, fax, data)
GMDSS type approved
Inmarsat – C (telex, data)
EGC SafteyNET
GMDSS type approved
Fleetnet 77 (voice, fax, data,
email) GMDSS type approved
Fleetnet 55 (voice, fax, data,
email)
Fleetnet 33 (voice, fax, data,
email)
FleetBroadband (simultaneous
voice & broadband data)
Fleetphone (voice)
Iridium
Voice services
Data services
Encryption
Fleet management
Personnel tracking
Asset tracking
Email
Globalstar
Voice services
Data services
Email
Encryption
Marine and Aviation
fit outs
Perceived weakness of Satellites
 Setup costs (equipment, above board and below deck)
 Call costs (voice and data services)
 Solar radiation damage (caused by sunspots and solar
flares)
 Earth bound interference (rain fade and volcanic
eruptions)
 Satellite life spans (7.5 to 15 years)
 Financial markets. Due to the high costs of
establishing, building and running a satellite network
companies can become debt ridden very quickly.
Cellphones
Cellphones can provide a convenient, simple to use and inexpensive
means of communications. However in a distress situation they have some
significant drawbacks:
 Most Cellphones are not designed for wet operations.
 They are point to point contact only not a broadcast radio like VHF.
 Response times by rescue services or other vessels will be delayed as
Police must first process the call and follow their standard operating
procedures.
 Network coverage at sea can be limited and short range.
Technology
VHF DSC
GPS Cellphones
TETRA –
Trunked Radio Networks