Another radio interference thread

MarkSF · #1 (**permalink**) 07-02-2011

My problem is that I get intermittent noise on my VHF, and the only way to stop it is by turning the squelch all the way up. I don't think it's someone else with a stuck mike, as it's happened the last 3 weekends.

Is it likely to be an antenna fault, or a source of electrical noise on the boat? Makes no difference whether I'm motoring or sailing.

I've ordered a handheld VHF to see if that suffers from the same affliction

mitiempo · #2 (**permalink**) 07-02-2011

I'm not a radio expert by any means, but if the interference is there when sailing experiment a bit. It is probably from something on your boat. When sailing turn the main battery switch off and see if that stops the interference. If so, with every circuit turned off turn the main switch back on. One at a time try each switch and see if you can find the one causing the problem.

jerryrlitton · #3 (**permalink**) 07-02-2011

Try changing channels 1st, if the problem goes away then you can say it is a stuck mic or the like.

Jerry

VetMike · #4 (**permalink**) 07-03-2011

Both the above posts are excellent and I would hope they help you find the source. Certain noises point to certain problems and if you could describe the noise to a tech (if the above doesn't work) that may help him decide where to start looking. For instance, a steady hum can indicate a power supply problem; interference that worsens when the engine speed is increased indicates that the alternator needs to be isolated and so forth.

MarkSF · #5 (**permalink**) 07-03-2011

Quote:

Originally Posted by VetMike

Both the above posts are excellent and I would hope they help you find the source. Certain noises point to certain problems and if you could describe the noise to a tech (if the above doesn't work) that may help him decide where to start looking. For instance, a steady hum can indicate a power supply problem; interference that worsens when the engine speed is increased indicates that the alternator needs to be isolated and so forth.

What I have is crackling that is intermittent and random, and makes it impossible to set the squelch. It seems worse on low channels, worst on 16. 78 is totally clear. I'm not sure the reception is that great either. Some transmissions I receive seem to be modulated with the same crackle.

The only thing that was on was the instruments, and I turned them off at the breaker. That just left the VHF on.

I think the best way forward is to try this handheld that's in the mail and see if its the same.

mitiempo · #6 (**permalink**) 07-04-2011

Maybe it is an antenna problem?

VetMike · #7 (**permalink**) 07-04-2011

Thanks. Crackling noise makes me think antenna. If the handheld does not exhibit the same problem, try this. Turn off the offending VHF. Clean the antenna connection on the radio and on the cable end and do the same at the antenna end. If the problem resolves or improves, your problem is most likely the cable connections got corroded. This common in marine equipment. The next step would be connecting another cable and antenna to the radio which, if the problem clears, indicates a bad cable and/or antenna. I know that this can be very frustrating. In a previous life I was a electronics technician in the Army and I worked on aviation systems. 24 volt, 12 volt transmitters, receivers, power supplies and each with its own idiosyncrasies. Wing flexion would cause fatigue in the antenna wires and we would go crazy trying to find the problem. Flexion along the antenna wire of a boat would have a similar effect