 It is a
legal requirement to have a
ship's radio licence and marine radio operator's certificate before
you use transmitting equipment from your yacht. On the ship's radio licence you
will find your vessel's international callsign and, if requested, 9 digit MMSI
number. To obtain a ships radio licence in the UK visit the Ofcom web site
click here and for marine radio operators certificate
click here.
Callsigns and MMSI
numbers are internationally allocated. If you know the vessel name, callsign or
MMSI number you can find the vessel particulars at the International
Telecommunications Union (ITU) web site.
click here for ITU ship database. |
Most yachtsmen
use the marine VHF radio and GSM mobile phones for their main means of
communications. Due to the time division multiplex access (TDMA) technology
used by GSM phones, the range of a GSM mobile phone is only 22 miles (35kms)
from the base station.
Marine VHF is the best way of
summoning help, you can contact the coastguard up to 50 miles off-shore and
talk to other yachts up to 15 to 20 miles on the open sea.
click here for a list of international
marine VHF channels
Before you can transmit using a marine VHF
radio from your yacht, you require a GMDSS Short Range
Certificate (VHF SRC). |
Marine SSB
(Single Side Band) is a popular means of communications for the independent
cruising yachtsmen and a must if you are planning to do bluewater cruising to
the Caribbean, Pacific or Mediterranean. The range of SSB is up to several
thousand miles and calls between yachts are free. There are stations around
which will let you make link calls (telephone calls) and even email and some
basic Internet service is available over SSB radio.
Having an SSB MF/HF
transceiver on board you are never alone, you can use your SSB radio for the
following: -
 Click here for a
listing of MF/HF SSB frequencies, includes distress, marine, aircraft and
broadcast stations.
If you want the capability of being able to
transmit on all marine frequencies which include MF/HF/VHF and satellite from a
yacht then you need a GMDSS Long Range Certificate
(GMDSS LRC).
Click here to find out
more about the Icom M801E SSB transceiver |
SSB shortwave
radio email systems offer a low cost alternative to mobile and satellite phone
systems and offers near global coverage.
Most SSB email service providers
work on an annual subscription basis, so there are no line-time or number of
bits transfer charges as with mobile phone or satellite systems.
To use SSB
Email you require an SSB radio such as the ICOM M710 or ICOM M801, a radio modem and a computer running Mircosoft
Windows . Using SSB email is as easy as sending email via your telephone line
or mobile phone.
Click here for more information on SSB email.
Click here for modem pricing information
|
To achieve good communications range and performance, it is essential that
the SSB transceiver is properly installed and the operator of the set has a
good understand of SSB radio.
- Power Supply.
- An SSB transceiver requires peak currents of 25 Amps.
Hence the voltage drop between the power source and the SSB transceiver should
be no more then half a volt.
- Good ground.
- For any MF/HF radio system to work a good connection
to ground or salt water is required. On a Steel yacht this is not a problem. On
a plastic yacht you need to mount 2 or more ground plates to the bottom of the
yacht and connect them to the ATU with 50mm by 0.5mm copper strip. Keep the
antenna grounding system completely separately from the DC or electrical
grounding system.
Click here
for copper strip and other antenna accessories
- A good marine antenna.
- A whip antenna works best as it gives vertical
polarization which is good for long range communications on higher frequencies,
8MHz and above depending on the whip length.
The backstay can be used if
properly insulated and a good RF connection is made. Due to the length of a
backstay performance is usually better then a whip on the lower frequencies,
2MHz and 4MHz depending on the length of the backstay.
Try and keep the
antenna well clear of any metal, including bottom section of backstay.
It is not practical to get an antenna
system on a yacht to work across a wide range of wavelengths. An MF/HF SSB
works on a wide range of frequencies (2MHz to 25MHz) and therefore wavelengths
is between 12 metres to 150 metres. An antenna which works on 12 MHz may not be
so good on 2MHz.
A good antenna on 2MHz is harder to achieve due to the
long wavelength (150 metres) and may not be effective on 12MHz due the
multi-wavelength length of 6 wavelengths long.
When considering the
antenna system, decide what frequency you are going to use the most and
optimize the antenna for that frequency. Avoid multiple wavelengths of half
wavelengths as the ATU may have problems tuning to these frequencies.
Around the Internet you will find many ways of installing an
SSB, what works on one boat may not work so well on another, the best advice is
keep it simple (KISS)!
Click here for HF SSB
Antennas Accessories
Attend a YachtCom
Long Range Certificate course to find out more! |
Mobile satellite
communications is now well established and works on your yacht just like a
terrestrial mobile phone. Mobile satellite phones should not be considered as a
replacement for conventional marine VHF or SSB communications.
Satellite
Facts :-
- Life times - Satellites have a limited life time,
dependent on fuel and orbit.
- Number of calls - The satellite is basically a telephone
exchange, it can only handle a limited number of calls.
- Coverage - Depends on technology deployed.
- Mobility - You do need an antenna above deck to receive
and make calls.
- Reliability - In the main good, but like any other mobile
phone technology do expect to lose/drop calls.
- Systems cost - It is very expensive to put satellites up
there and maintain them.
More information on
Mobile Satellite Communications |
DSC is basically a paging system which you can use to call other
vessels or use to make all station safety, urgency and distress alerts.
VHF
DSC radios are starting to become popular with yachtsmen, mainly because you
cannot buy standard VHF fixed sets any longer. There are no handheld VHF DSC
radios on the market.
MF/HF DSC is not very popular with yachtsmen due
to size, weight and cost. However, ICOM have a radio called the
IC M801 which
is a complete marine SSB transceiver with built in DSC functions.
Before
you can use a DSC marine radio you do need a radio operator's certificate,
these are GMDSS Short Range Certificate for VHF or
GMDSS Long Range Certificate for MF/HF & VHF.
VHF DSC
 |
MF/HF DSC
|
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Copyright
Bob Smith 1998 -
2007 |
