Batboard

I have searched the new version of the FCCs part 90 and can't come up with an answer. This is in ref to a public safety freq. on 155 mhz.

Years ago, (like 10 or 15 years ago) a "mobile only channel" on VHF, would be used as an input to a repeater. If a base station was to license on it, a "special condition" was added to the new base sta license stating: Licensed on a secondary basis to other mobile stations if interfernece is caused. (Or something to that effect). Meaning, if the base station caused interference to the mobile only input system, the new base sta would have to alter, modify or shut down until the interference was reduced or eliminated.

I can not find this any where in part 90. And it was there at one time. And it is no longer on a license that had this special condition attatched to it years ago.

My question is: Does any one know if they droped this from part 90? Does the FCC no longer protect the VHF "mobile only" channels?

Thanks all for any help or comments.
Pete

There is still protection of the mobile only channels, but I don't think it's done by the FCC, rather by the channel coordinator in your area. A customer of mine had been squatting on a VHF freq for several years and was paid a visit by the FCC (responding to an interference complaint... the source was actually 3 blocks away... guess the FCC can't read a map) for non-licensed operation. We got the ball rolling on getting him the proper license and when the license went to AAA for coordination they told us 1) his "current" channel is mobile-only and 2) there are no wideband freqs left open here in LA and he was assigned a narrowband freq.

The answer to your question has multiple aspects, and it is impossible to provide a definitive answer without knowing all the details about your particular situation. Hopefully, others who have specific experience with Public Safety Radio Service license grants can provide more specific information.

But it sounds like in the previous situation there may have been co-channel licensees inside your authorized operating radius and the FCC was simply disclosing that to you on your license. It may also be that these incumbents may have been licensed in a way that wasn't absolutely consistent with you...maybe their repeater output on your input, or their input on your output, or something similar. Remember that frequency allocations for repeater pairs on VHF historically haven't been as consistent (in terms of frequency separation and so forth) as those in the other bands.

In the current situation, perhaps you no longer have the co-channel licensee, or perhaps if you do, they have changed their operation so that it is no longer inconsistent with yours, or perhaps the FCC simply no longer applies that notation to licenses.

You don't indicate your location. If you are north of "Line A" there may have been special conditions on your previous license or special operating notes. I have an itinerant grant on a couple of VHF frequencies, and my license states that I can operate anywhere within the US, but that I may be subject to interference north of Line A, (since some Canadian repeater pairs are still operating on those frequencies). My UHF itinerant grants prohibit operation north of Line A.

Regards,