Which makes me wonder if it is really a trunking control channel. Normally there would be some evidence of the control channel 24-7 for the system to be useful. But this one keeps disappearing.
There are P-25 test signals that are used for coverage testing and Bit Error Rate information that look and sound a lot like control channels, but only show NAC data and not much else.
- Chris
that is certainly a good possibility, not that i was necessarily aware of that per se. the only experience i have had with anything like that was a few years ago where apparently a tech did a oopsie on a rarely used tower for a system in my area, but it was not broadcastiing a NAC at the time, just this weird noise that i presumed was of a completely different nature, on the CC and VC's for that tower simultainiously. i would have to refer to trumpetman for details on whether that was the same type of thing you are suggesting, but he indicated it was somesort of test mode.
anyhoo, the signal disappearing, at least from my locale is just due to the conditions coming and going as far as i can tell.
i haven't mentioned this yet, due to the dark comedy of errors, and hard learned lessons of unmentionable situation, but i was able to briefly receive the same (audible same) from a high elevation point two nights ago, most unfortunately, with a bc125at. i had no intention of doing any scanning that night, only take pics of a storm system approaching, overtaking my position and soaking me wet in the process.
i threw the cheapest scanner in a ziplock in my backpack as an after thought, knowing i wouldnt use it. it takes 45 minutes hiking up to this place, so of course, the storm system halted and petered out. boredom quickly set in. long story somewhat shorter, i received what sounded like a CC on 172.3, very variable fade, from approx 2000-2010h local. first time since fri morning. ugggghhh... back to the car, dump camera gear, grab all radio gear, back to the top, 1.5 gallons of sweat and an hour and a half later back at the top, there wasn't even a whisp of the signal to be found.
not to be simply satisfied with failure, disappointment and all sorts of exhaustion, just in case the signal faded back in, i wanted to be ready. i decided to whip-out a quick P25 system, so i could use the T-Sys analyze mode, in my new-to-me and rather confusing WS1040, doing the programming by memory, of which i have little. (1040 manual didn't make it out of the car on trip #2)
and while it hardly needs to be mentioned, as you may have already guessed, i heap error-ed myself, bricking the Ws1040 (unforgiving little goomer) in the process. ....yeeeeaaaa.... Running low on things left that could go wrong (others omitted here for brevity) I finally decided, this was not going to be the day, trudged back down, and was home by midnight.....
i really have no clue if there is any advantage to that location in this particular situation, but my next trip i will packing 2 kitchen sinks, just in case, and will report any findings.