The first thing to mention is that there is a legal requirement for operating a VHF radio aboard your boat and you will need to pass a fairly straightforward exam. A useful booklet printed by the RYA explaining the syllabus is a good start, day courses are run through them, also or you could try your local college which often hold the same exam at a much reduced cost. Whichever way you decide to go once you have your licence you will also have a good understanding of VHF and distress calls. This will stand you in good stead should an emergency situation arise and other then a lifejacket a VHF radio is probably the most important item of equipment a boat owner should possess.
There is a lot of in depth information on VHF transmitting but the following is a guide outlining the basics. I won’t go into detail on the choice of radio, suffice to say that it must be in good working order and if it has the DSC feature and is interfaced to a plotter then all the better – one press of a button to send a mayday giving your precise location does give a great peace of mind should the worse happen.
Of equal importance to the set is the choice and positioning of your antenna, after all if no one can hear you then you may as well be talking to yourself, and in an emergency situation you need to project your signal as far as possible to enhance the probability of some assistance. The range of your antenna will depend on a couple of factors, the first being the height you can position it – in short the higher the better. The second is the quality of the antenna itself – top brands such as Shakespeare will often out perform the cheap options that are available. Whichever antenna you choose it should be coupled with the correct size marine grade coaxial cable, too thin or poor quality cable can affect performance as can the length of run, although this is not usually a problem on a small fishing boat.
Most antennae that will be fitted to a typical 16-21ft boat will be a maximum of 8ft in length and usually 3db or 6db, either of which is ok.
The fitting of a VHF radio and antenna is well within the capabilities of most boat owners, if you have a basic tool kit the only other useful item is a soldering iron. Site the radio somewhere it will be easily accessible, it’s always a good idea to show crew where it is and also how to make a distress call.
As already mentioned, position the antenna as high as is practical, also keep it upright, not angled back or you won’t get the best performance from it. Use a good quality PL259 connector, gold plated ones are particularly good, and make sure all fittings are correctly attached.
Below are a few photo’s which give a guide to fitting the coaxial to the connector and also a couple of fixing types for the antenna.
First offer your coaxial end alongside the connector to give you your measurement
The outer plastic jacket is removed leaving it around 5mm short of the length of the connector
The wire mesh is then pulled back making sure there are no loose strands sticking forward, and 7mm of the centre core insulation is removed
At this stage I tin the end of the central core with a little solder.
The coaxial is then carefully pushed into the connector and the last 5mm is screwed onto the outer plastic jacket.
If you have measured correctly the inner centre core should sit flush with the end of the connector pin.
I then drop a little solder in the end of the pin to help hold things in place.
There should not be continuity between the pin and the body of the connector; this is easily checked with a multimeter.
To finish I wind a few turns of insulation tape around the base where the connector meets the coaxial. There are a number of ways to fix your antenna – mounts in stainless or plastic are probably the easiest option, incidentally the ferrule on your antenna should match the mount
The antenna can also be fixed via brackets, rails or whatever you like really, just as long as what is used is strong enough and secure enough to take the rigours involved on the water
If you do fit a new VHF or antenna then do a quick radio check before you head out.
By Wayne Comben