InterceptRadio.com Forums

I'm down here in Boise again for the holidays. Thanks to my Pro-2006 d-tap I figured I'd monitor a few of the trunk sites down here.

There's one that is run by a commerical outfit (Gem State) and it serves private customers.. taxi, airport shuttles, etc.

The site runs in the 857 range. Nothing unusal there. By accident, I was scanning the air band last night and I found a trunking site on 123.285mhz. I thought this was a mistake (an image or something) but it doesn't match the multiples. This site was the Gem State site. The SysId's match. The Gem State control channel is 857.2875. I do believe this is a IIi hybrid site.

Then I thought since they do have some Airport-related services, I thought they might simply rebroadcast the signal. The signal modulation is actually NFM though the trunking software was able to decode in AM as well.

Any reason why they'd do this? I mean do they make trunk radios that would operate at 123mhz? That just seems odd to me?

There's nothing else that's unusal ... I can punch in the control channel and listen just fine on the 396T.


-Nick

Airband is AM only and nothing is trunking there. Its possible (but doubtful) someone is retransmitting there. You most likely are dealing with an image. Keep in mind you have some constant carrier sources (VOR, ATIS, etc) which can contribute to mixes.

Rich, I think the AM band is 25khz steps. This would fit in-between.

It might be an image... but it's one hell of a strong image. Like you I don't see the point of rebroadcasting it. I'm not even close to the airport so I'm surprised the Pro-2006 would pick something up that strong.

The US band is 25khz but the number of 8.33khz radios has been increasing as equipment gets replaced. 123.283 would most likely show up as 123.285 on a 5khz step radio.

I've picked up the KC/VC system in the low 30.000MHz range while sitting in a parking lot in Issaquah.

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