VHF radio noise

[biederboat]

I have two different VHF radios (permanent installation with a standard 8' antenna) that make emit a cycling static noise intermittently. One of the radios and the antenna were just transferred from another boat where they worked fine but it also made the same noise with the other radio and the original antenna. The radios seem to work okay, I sent and received a radio check from the coast guard at a time when it wasn't making the noise.

The noise is like a static signal that goes one for about 1/4 of a second and then stays off for about a 1/2 second and does that continuously. Also, it doesn't do it on all channels but when it does, always on 16/9.

Any clues?

Thanks,
Biederboat

[Duke]

More than likely interference from another electrical component mounted nearby. Whats mounted close to the radios?

[biederboat]

Good point, never thought about that. There's the general switches and gauges, a GPS (handheld that is usually off), but that's about it. The VHF is mounts below all this other stuff. Would it be the antenna wiring or the unit itself that is picking up the stray signal?

Thanks,
Biederboat

[Duke]

Not really qualified to answer your question. This is a pretty common problem. Guys with more radio experience will give you better information.

However, one thing to try if you're able...one-by-one, switch off each of the surrounding components while monitoring the radio. By the process of elimination, you may be able to find the offending device, then come up with a plan to eliminate the interference.

Good Luck!!! If you get it resolved, post it.

[SouthCoastStu]

Does it make a difference if the motor is off?

[StickFish]

Sounds like classic electrical interference.

is the radio wired direct to the battery or through you patch panel up front? Next the antenna connector how is it attached to the coax? If it isn't soldered on - it needs to be (broken ground shield will exhibit the same . Which antenna are we talking about? If its a Shakespeare 5206 - send it on its way they are junk. Pm me if you need some help

[chucks electric]

hello, one of the most common causes of this is an alternator, sometimes you will find a large capacitor attached to the electrical output terminal this is a bandade and will not correct the problem for long the second is leaking plug wires yes they do leak rfi. take an am radio and move it around the engine and helm area and see if you can isolate where you get the most static. the alternator is an easy one. take a digital volt meter and turn it to a/c 2 volt scale attach the red lead to the output terminal at the rear of the alternator, and take the black lead and scratch a clean spot on the case of the alternator, and with the engine running you should see not more than 0.1 volt any more than that and you will have noise. start here and then I'll tell you were else to check.

[Boats]

Originally Posted by biederboat

The radios seem to work okay, I sent and received a radio check from the coast guard at a time when it wasn't making the noise.

Just FYI... The Coast Guard may not the best organization to call for a radio check.

Why??? Because we have 4 high-tower antennas placed at various locations around the Willamette and Columbia rivers. One is located up on Skyline. We can hear boats clear out of Seattle!

Therefore... Unless something is really, really wrong with your radio... The Coast Guard should hear you loud and clear.

Try arranging a radio check with the guys over at Rogers Marine Electronics. They may be a better indicator of your ability to transmit and receive.