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-   -   Getting AM radio stations on VHF Radio (http://www.sailnet.com/forums/electronics/65536-getting-am-radio-stations-vhf-radio.html)

L124C 06-12-2010 01:33 PM

Getting AM radio stations on VHF Radio
 
I'm getting a AM Radio station clear as a bell on Chanel 22. Any ideas why? The other channels on the VHF work Perfectly.

ottos 06-14-2010 09:21 AM

What is your location? In the US, 22(A) belongs to the Coast Guard, so if someone were keyed up and rebroadcasting, somebody would probably have found them by now.
Is anybody else in your area reporting the same?

How long has this been going on?

How far away is the transmitter for that station from your boat?

Next - All your other electronics are turned off, right?

oceanscapt 06-14-2010 10:13 AM

It could be a harmonic of the AM station but to go from the 560-1720KHz AM radio band to the 156MHz marine band is a big jump. Add in the AM to FM conversion and I'm more than curious. And since most VHFs are now synthesized frequencies instead of crystal controlled, it's intriguing.

It's possible that the radio station has a transmitter problem but the first thing to do is see if your radio is OK on CH 22.

How close to the radio is your boat?
If the VHF is portable, can you take it a few miles away and see if the problem persists.
Have you tried another VHF at your problem location?

wind_magic 06-14-2010 10:20 AM

Maybe someone is retransmitting the station - CBer's do that sometimes, if their favorite song comes on the radio they'll hold the microphone up to the radio and retransmit the audio over the CB, very annoying. People who do this kind of thing seem to believe they are performing some kind of public service and don't understand why people get irritated about it.

oceanscapt 06-14-2010 11:15 AM

Quote:

Originally Posted by wind_magic (Post 613014)
Maybe someone is retransmitting the station - CBer's do that sometimes, if their favorite song comes on the radio they'll hold the microphone up to the radio and retransmit the audio over the CB, very annoying. People who do this kind of thing seem to believe they are performing some kind of public service and don't understand why people get irritated about it.

Hadn't thought of that wind_magic but channel 22A in the US is a heavily used Coast Guard channel, so I'd think the FCC would be less than amused at the 'rebroadcast", and the anchorage/marina frequency police would be all over that too.

The author didn't say whether the interference was constant or intermittent. Outside the US, the rules, if there are any, are far less enforced.

hellosailor 06-14-2010 07:42 PM

L1, try another VHF or ask another boat to tune it in. If your radio is the only one receiving it--your radio needs repair. (Unless that's a very powerful station with a transmitter located very close to you, in which case all sorts of overloads have been known to happen, unless you have a very good radio.)

wind_magic 06-14-2010 07:46 PM

Quote:

Originally Posted by oceanscapt (Post 613039)
Hadn't thought of that wind_magic but channel 22A in the US is a heavily used Coast Guard channel, so I'd think the FCC would be less than amused at the 'rebroadcast", and the anchorage/marina frequency police would be all over that too.

The author didn't say whether the interference was constant or intermittent. Outside the US, the rules, if there are any, are far less enforced.

Before we entered into this new age of people's cell phones calling each other when they sit down on them, we used to be in an age where people transmitted for days (sometimes) when they accidentally put something on the microphone and the button got pressed. :D

oceanscapt 06-15-2010 11:30 AM

One of the more intelligent mods to radios, especially VHFs, was the 5 minute timer. :D

L124C 06-25-2010 01:05 AM

I asked a dock mate to try his VHF on 22, and gets the same AM Radio station! The marina is below a mountain which has several broadcasting transmitters on it. They sit at 1000 feet, and are probably 3 miles from the marina. Strange! I'll ask the Harbor master if he is aware of the situation.

bljones 06-25-2010 01:07 AM

Have you tried removing your tinfoil hat? :)


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