Ventura Activity on Pre-Rebanding CMARS Input?

[kj6psg]

I'm hearing a fair number of transmissions on 822.5375MHz PL 123.0, the input for pre-rebanding CMARS Green, here in Ventura with decent signal strength, somewhere in the -95dBm ballpark. I can only hear a single base station (which appears to be linked via wireline, showing 2175 Hz notch), but they're communicating with other portable operators that are well below my noise floor. CMARS rebanded here around 2013. I can't locate any signal on either the pre-rebanding (867.5375) or post-rebanding (852.5375) output, though LTE interferes with reception on the pre-rebanding spectrum. The rebanded South Mountain CMARS site is one of the strongest transmitters I can hear on 800 MHz, so it isn't coming out there; and by extension there's no output from South Mountain on the pre-rebanded channel. So, who is it, and what are they talking into?

Some audio is attached.

 

[iscanvnc2]

You won’t believe this, but here’s what’s happening. I don’t explain ’em, just report the facts. Using 3 scanners helps.

You are hearing the “dispatch” for the Calif Youth Authority west of Camarillo & NE of Oxnard.

Listening to CYA output (859.2625), input (814.2625), & OLD CMARS input (822.5375), I hear dispatch loud & clear on 822.5375 PL123.0 & 859.2625 PL 131.8 but not on 814.2625. Occasionally a unit would exceed threshold on814.2625 to show the 131.8 PL.

Background: Prior to rebanding I received CYA dispatch (no units) on CMARS simultaneously with the CYA repeater. Never could figure out the logic in that.

CONCLSIONS:
1. Dispatch on 822.5375 is a base unit to put in a strong signal (max bars on 996X) compared unreadably units on 814.2625.
2. Dispatch on 822.5375 serves no purpose that I can discern.
3. Dispatch is hard wired to the CYA repeater.

 

[kj6psg]

That would make sense given the traffic. I was looking around with two SDRs (an excellent tool for finding inputs, if used right) and couldn't find a match. I bet CYA used CMARS in the past, but got their own repeater sometime before rebanding. If comms center is off-site (which is how it is with DPR, not sure about CDCR), they were tied into a remote base somewhere to talk into CMARS. When they moved to the new repeater, the CMARS transmitter was left connected while comms center can communicate to the repeater transmitter directly.

Let's just hope the techs didn't put up a 822.5375 receiver just for the purpose of not having to change the comms center remote base's channel or location.