Which VHF?

[Matthew P]

Which VHF?

With coastal cruising in mind I’m keen to extend the range of my VHF beyond the “line of sight” that my hand-held offers.

My first thought was to use a plug-in extension with the antennae attached to the top of the mizzen but the bother of having my several year old hand-held tethered with a frequently used and therefore wear-prone aerial connector plus plug and cable power losses and limited battery power make it un-worthwhile. 

Fixed sets seem a better solution.  With a budget of £150 (excluding batteries and wiring costs but including antennae) my questions are:

a)   What makes of VHF are dependable?

b)   What features are important? Some of the features I'm interested in are systems for alerting vessels ships to my invisible presence and, hopefully never needed, getting help quickly at the press of a button, operated by a cold-fingered, seasick and inexperienced crew.

c)   Any tips for installation including battery supply, connectors and antennae type and positioning

I hold an underused and almost seven-year old operating licence but I’m not familiar with all the acronyms and buzzy words associated with radios so a simple explanation of desirable features will be very helpful.

Matthew
BR20 Gladys

[Peter Taylor]

Hi Matthew,

As it would appear that you realise, all VHF is "line of sight" so improving your range is mainly a case of getting the aerial higher. On the "high power" setting a fixed VHF will give you 25W whereas a handheld will give you 5W so there is a bit of a gain there too. But height is the major factor.

I'm not a radio ham and I got totally confused with regard to choosing an aerial and still am. Many aerials come with fairly low grade (but apparently adequate) coax cable. Be aware that in many cases this cable is part of the aerial tuning and you are not supposed to shorten it. If you don't want to slow Gladys down with the weight of 20m of coax you might want an aerial that doesn't come with cable. Based on Practical Boat Owner in October 2012 I bought a Shakespeare "Squatty body 5215" antenna.  That means you have to have a plug near the antenna in which case use self amalgamating tape to keep the water out. However going that route means you can't save space by using a combined windex and antenna at the mast top. For the best choice you need to ask someone who knows more than me!

ICOM seem to have the best reputation but my Standard Horizon has so far been reliable and, when I bought it, offered better value than an ICOM, things may have changed.

Features:
 A VHF radio will not alert ships to your presence (unless you radio them!); for that you need an AIS transponder or a radar transponder, or both. However a radio that receives AIS can show you where there are nearby ships. Usually the radio display of AIS positions is fairly dire but the radio can send the AIS data to a chart plotter which will then display ship positions on the chart. I find that very useful in Southampton Water for finding where the high speed ferries are - they do 35 kts so I like to find them before I cross the shipping channel.

For "help at the press of a button" you need a DSC radio. DSC is Digital Selective Calling and allows you to call another station by entering its "telephone number" (MMSI number). You probably won't use it for that but it does give you a distress button which is fairly simple to use. Sending out a DSC distress call will sound an alarm on all receiving DSC radios and switch their frequency to ch.16 so you can send out a voice mayday if you have time. If not, their display will simply show your MMSI number and your position if your radio knows it. If you have filled in a CG66 form the Coast Guard will be able to tell the lifeboat what your boat looks like as well as where you are.

So in order to send out a useful distress message the radio need to know your position. You have the choice of feeding the position from your chart plotter or, better, choosing a radio with built in GPS - such radios are comparatively new. If you go the chart plotter route for AIS and/or GPS make sure that the radio and the chart plotter will talk to each other!

If you have an old short range VHF licence, to be strictly legal, you are supposed to upgrade it to a Short Range DSC licence. You might be able to do that at a cut price rate - or you could just read the manual (I didn't say that!).  A DSC radio simulator is available on the web "http://www.nauticalsoftware.com/training-software/gmdss-vhf-simulator.html" for £25 (or there is a free version elsewhere) - it allows you to practice sending a DSC distress without people coming to rescue you - or you could just read the manual!

So to summarise - I'd buy a fixed DSC radio with AIS reception and built in GPS - but I don't know if that comes within your budget!

Peter

[Graham W]

Matthew,

As your financial adviser, I have to tell you that unless you are lucky enough to pick up something secondhand (somebody upgrading to DSC perhaps), you are unlikely to get a complete fixed setup for £150.

Fixed VHF radios (without DSC) are in your target price area but you also have to budget for an external aerial and cable, which will add another £40-£50.

I think you already have a handheld VHF?  Have you considered using an emergency aerial instead, plugged into that?  Like this one http://www.force4.co.uk/vtronix-shorelink-emergency-vhf-antenna.html#.WMl-QRicYUY. When you need to extend your range, you run the aerial up the mast using your spinnaker halyard.  I've got a Vtronix which so far I have never had to use.  If I ever get into a situation where I need to use it, I wonder if I will have the time/presence of mind to find the aerial, plug it in and then fiddle around with my spinnaker halyard.

Another £50 or so will get you a radio with DSC, which I thoroughly recommend.  As Peter says, your broadcast position can be picked up automatically at the touch of a button, assuming that you are within range.  It could be a lifesaver.  If you want AIS as well, that's much more expensive.