Commercial Radio Station Broadcasting on Marine VHF 22

[rardiH36]

Out on SF yesterday during the Cup Race, I pushed through my hand-held's VHF 22 while tuning to VHF 20 to listen to the America's Cup commentary.

On VHF 22 I was surprised to hear AM/FM KCBS Radio's (All The News All The Time) highway traffic and weather report "On the 8's". I went back to Channel 22 several times over the next couple of hours -- a good clear signal each time.

I did an internet search this morning and found the attached discussion. I will have to check that I haven't inadvertently set my VHF to international mode. In any case, I now have convenient news radio access while at the helm!

http://www.sailnet.com/forums/electronics/65536-getting-am-radio-stations-vhf-radio-2.html

 

[Stu Jackson]

rardi, from reading that thread, doesn't it mean you have your VHF on International?

 

[Allan12210]

Someone was probably sitting on their mic key and had another radio on in the background. VHF marine frequencies are not close to AM commercal broadcast (even on international).

 

[rardiH36]

... I will have to check that I haven't inadvertently set my VHF to international mode...

Stu:

Per the above part quote from my opening post ... yep, looks that way. Will have to check next time at the boat.

I wonder if commercial radio can be found in other metropolitan areas on International mode?

 

[rardiH36]

Someone was probably sitting on their mic key and had another radio on in the background. VHF marine frequencies are not close to AM commercal broadcast (even on international).

Allan:

Creative thinking! But the audio quality of KCBS's broadcast I was hearing was much too good for that option.

 

[jack.ott]

Cherubini 44 great boat

 

[jack.ott]

Maybe an open Mike

 

[MrUnix]

If you were close to the transmitting broadcast antenna, you could have been experiencing VHF image interference.. their broadcast frequency is only about 50Mhz away from VHF channel 22, and is close to the first IF frequency used on a lot of VHF radios (45-55Mhz depending on model). I doubt seriously that they were actually broadcasting out of band.

Cheers,
Brad

 

[nolasafari]

If you were close to the transmitting broadcast antenna, you could have been experiencing VHF image interference.. their broadcast frequency is only about 50Mhz away from VHF channel 22, and is close to the first IF frequency used on a lot of VHF radios (45-55Mhz depending on model). I doubt seriously that they were actually broadcasting out of band.

Cheers,
Brad

No matter what they can expect a visit from the FCC. Time for them to have an RF engineer look at their equipment.

Jim

 

[Chris Patterson]

Images are common in the VHF band, that's why frequency allocations are supposedly restricted. It's simple enough math from your desired freq to determine what the image freg is, and who it may be. Blocking or interfering with it may be challenging. But as common as it is, RF guys still trouble with it. I think it's really voodoo..

 

[rardiH36]

Back at my boat today, the KCBS pickup on VHF 22 happens only on the international setting. Does the same on my fixed VHF at the nav station when switching to internatioal. My slip is several miles from the central bay where I picked up the Channel 22 broadcast yesterday. Looking at the frequency chart, for each Channel, yes the mHz's are different between USA/Int/Can for many of them. Included in the other forum thread I gave the link to in my OP was a reference that KCBS might be using the frequency as a link between their studio and the transmitter.

Anyway, if there is any commercial radio station in the SF Bay area that is useful to also get on the VHF, 24/7 news is it!

 

[jackever]

Back at my boat today, the KCBS pickup on VHF 22 happens only on the international setting. Does the same on my fixed VHF at the nav station when switching to internatioal. My slip is several miles from the central bay where I picked up the Channel 22 broadcast yesterday. Looking at the frequency chart, for each Channel, yes the mHz's are different between USA/Int/Can for many of them. Included in the other forum thread I gave the link to in my OP was a reference that KCBS might be using the frequency as a link between their studio and the transmitter.

Anyway, if there is any commercial radio station in the SF Bay area that is useful to also get on the VHF, 24/7 news is it!

KCBS is 106.9 MHz add the 55 MHz IF =161.9 MHZ Int 22 receive is 161.7, close enough perhaps interesting that it could be on 26 even better, but as you mention may be the Station to transmitter link, thought those are ususally directional microwave.