RV Stereo Antenna cable issue

wa8yxm wrote:
I know the relation between TV and FM bands in fact pre-digital I'd often tune in Channel 6's audio carrier on FM radios).

But I'm not convinced of the adjacent channel interference issue. Normally if there is a channel six the FCC does not assign 88-90 MHZ in the area. Of course now the FCC is trying to discourage the use of Channel six for TV.. they want to re-sell the spectrum to other services,, but that's another issue.

That said, Filter/block or just not amplify.. All have the same results.

My understanding is that only the VHF HIGH BAND 7-13 analog)is now allowed for ATSC OTA. 2-6 were removed from active TV broadcast with perhaps the exeption of some analog "translator" transmitters which were grandfathered for a period of time after the ATSC mandate.

That is pretty well reinforced by the mere fact that antenna manufacturers are no longer making TV antennas which reach the 2-6 channels and even finding a TV/FM antenna has gotten rather difficult since many antennas are now cut for 7-13 VHF HI and 14-60 UHF..

In the olden days of analog TV there was indeed problems of interference from the FM radio band when in or around large metro areas where you have all VHF channels filled and even the FM channel alotments filled.

But keep in mind that there ARE a lot of frequencies between the FM radio and Ch7 TV which include amateur radio, Fire, Police, Business, Airline/airport, national weather service..

The decision to not amplify the space between 6 and 7 was up to the antenna manufacturer and depending on how much gain (or lack of gain) which affects the directionality of the antenna it may have been a good thing.

Generally you only see the space between 6-7 not amplified on small antennas which often were nothing more than a dipole..

I know the relation between TV and FM bands in fact pre-digital I'd often tune in Channel 6's audio carrier on FM radios).

But I'm not convinced of the adjacent channel interference issue. Normally if there is a channel six the FCC does not assign 88-90 MHZ in the area. Of course now the FCC is trying to discourage the use of Channel six for TV.. they want to re-sell the spectrum to other services,, but that's another issue.

That said, Filter/block or just not amplify.. All have the same results.

Thanks for all the info., The antenna coax is hooked up, but like I said, it acts like there is no signal at all & I know it's not the speakers. Even if the FM was blocked, the AM should pick up. I gave up & just listen to my computer until I get a good selection of CD's.

wa8yxm wrote:
Generally the Stereo is NOT hooked to the antenna.. REASON.. Winegard, in theire infinite wiseom, or lack theeof.. designed the amplifier in the antenna so it would BLOCK the FM radio band... Please do not ask why.

Actually they do not "block" the FM, rather it is NOT AMPLIFIED. Overall the FM band is "attenuated" by about 20 DB since the amp has a gain of about 20 DB for TV bands.

It was done not because Winegard has a hate for FM users but to PREVENT FM interference from ruining your TV reception.

That is due to the fact that the FM broadcast band was right smack dab between analog channel 6 VHF Low (88 mhz) and analog channel 7 VHF High(174 mhz.

FM broadcast from 88 mhz to 108 mhz and many public service, Ham, business, fire, police, airplane radio bands from 108 mhz up to 174 mhz if amplified can easily overload a TVs tuner which will cause severe interference for the TV..

Not unusual for small antennas with a built in amp to filter down the frequencies of 88 mhz to 174 mhz since these small antennas typically do not have much gain by themselves..

For the OP, some RVs will have a small external FM "duckie" antenna on the roof or side of the RV..

If your RV does not have either the manufacturer may have simply run a short piece of wire out of the stereo around the cabinet. In this case you can add your own external antenna and connect it to the stereo for better reception.

The stereo is in the living room cabinet of the camper, a Linear LS7500CD with the coax antenna, the coax goes into the wall but I don't know where it goes from there, I have searched for wiring diagrams but no luck.

Do you have separate house and dash radios?

Dash radios the plug is called a motorola plug. it is the same size around as an RCA plug only the center pin sticks out and the entire plug pokes into the socket.

House radios it will be either two screws or a coax fitting or one set of each (one for AM one for FM and the RV's antennas DO NOT CONNECT, a seperate antenna should be included, likely a twin-lead folded dipole. If you remember the old days fo flat wire TV antenna lead that hooked to two screws (this still does) it is a big letter "T" made with that same type of wire. hooks to two screws on the radio.. Usually. Of course 75ohm Coax connections are possible as well.

Thank you all for the quick replies. There is a round piece of plastic covering something on the roof right above the stereo area, so I'll check it. The black cable is hooked up into the exterior antenna socket on the stereo. The plate (winegard) on the wall above the stereo has 3 gray cables & other wires hooked up to it but no black one. I don't understand why FM would be blocked. I found the manual of the stereo but it doesn't say anything about the FM problem.

My 5'er has two roof antennas. One Wineguard TV antenna and a 2nd short whip antenna for the radio. Both cables come in behind the TV.

Generally the Stereo is NOT hooked to the antenna.. REASON.. Winegard, in theire infinite wiseom, or lack theeof.. designed the amplifier in the antenna so it would BLOCK the FM radio band... Please do not ask why.

My Cougar and many others have a loop of antenna wire tied up behind the stereo cabinet. Works fair, I put a regular antenna on the roof to pull in weak signals. Chino