Fixed VHF not performing

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Laundryman

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17 Dec 2007
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Live in Hemel Hempstead, Boat is in Haslar.
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My Radio Ocean 4800 is less than 2 years old and doesn't work as well as it should. At the call point on the approach to Port Solent I couldn't raise the Marina yet i could on my handheld. I called CG for a check and they responded by saying that I was very weak. Yes I am on 25w. Before I rush out to buy, please can you offer a simple but definitive method of checking whether it's the Radio or mast antenna at fault. Thank you. Alan
 
Laundryman said:
My Radio Ocean 4800 is less than 2 years old and doesn't work as well as it should. At the call point on the approach to Port Solent I couldn't raise the Marina yet i could on my handheld. I called CG for a check and they responded by saying that I was very weak. Yes I am on 25w. Before I rush out to buy, please can you offer a simple but definitive method of checking whether it's the Radio or mast antenna at fault. Thank you. Alan
Click to expand...

Try it with on a known good antenna ! ... The emergency one packed with your flares!
 
Hi..
PM me when you're next going to be on the boat and I'll be happy to pop round with an RF power meter and SWR analyser.
With that we can quickly see exactly how much power your radio is putting out, how much is getting to the antenna cable, and how much might be being reflected back due to bad connections or antenna itself.
It will only take a couple of minutes to test and then work out a plan from there..
 
Just re-read the thread.

We could test the emergency antenna at the same time.

I found my short stubby emergency antenna to be 'not the best' after many years of it sitting in the emergency locker.. so now have a standard sized antenna mounted on a pushpit pole as well..
 
Laundryman said:
My Radio Ocean 4800 is less than 2 years old and doesn't work as well as it should. At the call point on the approach to Port Solent I couldn't raise the Marina yet i could on my handheld. I called CG for a check and they responded by saying that I was very weak. Yes I am on 25w. Before I rush out to buy, please can you offer a simple but definitive method of checking whether it's the Radio or mast antenna at fault. Thank you. Alan
Click to expand...

I had a very similar problem with my VHF. I had fitted a replacement V-Tronix Hawk VHF Aerial & Wind Indicator at the same time as installing the new radio and it had never worked satisfactorily. I don't know if you also have this aerial, but I mentioned the problem to a marine electrician acquaintance and the first thing he told me to check was that I had tightened up the plastic nut that attaches the cable to the masthead unit sufficiently. I had only tightened this by hand as I didn't want to strip any (plastic) threads, but he told me that this was unlikely to be sufficient.

I went up the mast with a pair of pliers and found that I could wind the nut - and hence cable connector - in quite a bit more without using undue force until the nut reached a firm stop. The result was a VHF in perfect order with an AIS range that (exceptionally) picked up a ship 30 miles away in the channel from Chichester Marina!

I think he said that the resistance between the 2 elements of the cable should be 10 000 ohms for this type of aerial if connected correctly. If it isn't, I imagine there would be no continuity. This was a while ago though and my memory isn't great, so perhaps someone else can confirm?
 
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