How to test a VHF Radio & or Ariel

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Ribtecer

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When I bought my boat it came with a very nice and quite modern Standard Horizon VHF Radio that "looks" only a year or two old.

Trouble is I cant get the bugger to work, it hisses normally when the squelch knob is turned up, but even on the edge of the Solent I can't hear anyone at all and I have tried a radio check.

Clearly it could be either the Radio or the Ariel, how does one check one or other or both please.

Thanks

Toby
 
Welcome back to boating.

Not a good sign that "it hisses normally when the squelch knob is turned up" as squelch is supposed to remove that hiss.

suggest you connect it to a friends aeriel to see if it receives anything. Do not do a further radio check, on your present set up, for if the aerial or wire is u/s it will stand a good chance of frying the transmitter.

for ship and user licencing , a good place to start is here

http://licensing.ofcom.org.uk/radiocommunication-licences/ships-radio/

http://www.rya.org.uk/coursestraining/courses/specialist/Pages/SRC.aspx
 
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Hi

You need somebody with an "SWR" meter (Standing Wave Ratio). You need one that works at 156 to 160 Mhz. This will measure the power being sent out and any reflected power back down the coax.

You can buy one on ebay £40 - £50 ish, but you would be far better asking locally if anybody has one. You could Google a local ham radio club. I'm sure you would find a helpful radio ham to come along and test it for you.
 
You need to first establish if the problem is the radio or the antenna. So, you need to connect the radio to a known good antenna, or connect a known good radio to your antenna.
Don't transmit on your set up until you've resolved the problem or you could damage the radio.
If the radio continues to hiss on a good antenna, send the radio for repair. If the radio receives on the good antenna, you need to then check the antenna installation on your boat.
 
Borrowed one of these £30, helped me find the fault.

http://www.ebay.co.uk/itm/MOONRAKER-SWR-270-100W-DUAL-BAND-120-500MHz-VSWR-POWER-METER-/300955692059?pt=UK_Mobile_Phones_Communication_Radio_Meters&hash=item46125b6c1b[/URL]Communication_Radio_Meters&hash=item46125b6c1b
 
If you disconnect the aerail cable from the radio and connect a piece of wire about 17 inches long into the socket you may find that you can hear stations reasonably close.
Or make up an emergency aerial (search on here) These should prove the radio OK. It is most likely to be the aerial at fault or more specifically the cable connecting it. good luck olewill
 
William_H said:
It is most likely to be the aerial at fault or more specifically the cable connecting it
Click to expand...

That would be my bet too, although a faulty radio is not impossible.

Modern electronics are pretty reliable, and the radio generally sits in a protected position below decks. The aerial cabling needs to stay unbroken, free of corrosion, and dry inside to maintain the dielectric. It has to do this while squeezed and pinched into small spaces, passed through often-dubious connectors, exposed to wind and weather, largely inaccessible for inspection, often assembled by a marginally- (and sometimes completely in-) competent DIYer, and sometimes protected by no more than a few turns of PVC tape over otherwise non-waterproof connectors.

It's nearly always the aerial.

Pete
 
Salty John said:
If the radio continues to hiss on a good antenna, send the radio for repair. If the radio receives on the good antenna, you need to then check the antenna installation on your boat.
Click to expand...
To make such good / bad test with a known good device is the best way.
A simple Ohm meter can examine one of the reasons:
When looking with the ohm meter into the connector to the antenna, you should see a very low resistance.
When there is a open circuit, the cable is broken. Go further an fix that.
The antenna has a DC short circuit with a coil.
Wilhelm
 
Thanks Chaps, very useful info, I will make an emergency AERIAL (not ariel) as per the advice, does it need to be a specific coax just for the test?
 
Well, to transmit effectively it needs to be 50 ohm cable. One made from 75 ohm (television) cable should receive OK, though - but why bother when the correct cable is easy to find?

I'd go along mostly with the suggestions so far, though I wouldn't let you try transmitting with my radio into an untested aerial assembly - it could damage mine! An SWR check will prove whether the aerial assembly is safe, but may not give the whole answer as to whether it is effective. First thing is to try your radio into a known good antenna. Although an emergency aerial will allow you to test it, if it works OK on another boat then your setup will have either a bad aerial, bad cable and/or bad connections. To be honest, if the mast is down for the winter, the simplest answer would then be to fit a brand new aerial and cable.

Rob.
 
I strange testing approach perhaps, but in my garage I have a CB radio complete with an aerial with what looks like the same plug as the VHF

Can I swap their aerials as a test without doing any damage? (I am not really bothered about damaging the CB but I am about the VHF)

Thanks again
 
Nope. Totally incompatible. The CB operates at a wave length of 10 meters and the marine VHF at a wavelength of 2 meters. It could be used as a receive antenna, but then so could any length of wire.
When transmitting, the length is very critical, to the millimetre to get the very best propagation.
 
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