P25 system testing on 451.1375 ?

[freqhopping]

"Logistics" and "4999" are the ones transmitting
There have been references to the Manassas repeater and Gainesville tower

The FCC DB show no records in MD, Pepco in DC, and a few power companies in VA, none of which are near Loudoun or Prince William counties.

Any ideas?

I don't know morse, but I'm trying to get a recording of the identifier so someone that knows can tell me.

Here it is

 

[DaveIN]

Sounds like V253. Did you miss part of it, like the first three letters?

 

[TinEar]

That's what I get too...V253. It appears to have 2 or 3 letters missing from the front if it's a callsign. In fact, if there's something missing, that V could also be the end of a 4 with the first dot missing. Just not enough of it there to be able to call it a callsign.

 

[ericcarlson]

It seems to me that you are probably hearing a Columbia Gas repeater on Fork Mountain.

WPPV253

-Eric

 

[freqhopping]

I used Scanrec to record the callsign. It must not have been quick enough to catch the beginning, so I'm going to let it record continuously.

Eric's suggestion is the most plausible at this point. If so, then why would a gas company be switching to a P25 system?



New recording
If this one got chopped at all, then it's at the end when that other noise breaks in. That noise breaks squelch frequently.

 

[n4jri]

Having digital is not unprecedented. There is a very strong transmitter somewhere near Farmville on 451.75 which appears to be the Southside Electric Co-op. Just as strong in South Hill as it is in Farmville.

73/Allen (N4JRI)

 

[dtscho]

Columbia Gas uses 452.1375 in P25 digital mode in Fredericksburg. I've heard digital on 451.1375 and 451.6500 as well.

Dave

 

[CCHLLM]

Though I can't actually decode the modulation in the 451.750 signal near South Hill, some of it shows up as a modbus sequence for SCADA transmissions on my laptop, while some of it looks like P25 voice. SCADA is quite common in the water/sewer/power/ utilities systems, whether analog or digital. In fact, some of the utility systems use a data talkgroup on their trunking systems for the SCADA traffic, while others use fixed simulcast channels. Either way, the systems can be P25.

The 451.750 freq is the same as one I have to maintain in SC, so when the data radio hears that freq or any others that are shared in other areas, it'll ID the format but won't decode the actual data nor will it do anything for voice modulation because the laptop is set up for a particular address and data subroutine.

 

[DaveIN]

I used Scanrec to record the callsign. It must not have been quick enough to catch the beginning, so I'm going to let it record continuously.

The audio level in your recording is really low, but I heard the same ID. It sounds as if the begining of the ID is still being cut off.

 

[TinEar]

I agree with DaveIN. Extremely low volume on the recording but it still only contains V253.

 

[n4jri]

I originally ran into 451.75 because it repeats 155.34 in Prince Edward County, albeit with CTCSS. But then I heard masked digital traffic and changed the PRO-96 over to FM, only to hear all sorts of discussion of setting up multiple transmitter sites and dealing with computers.

I'm intrigued that such a strong and widespread system has shown up on a freq used for a public safety transmitter/receiver link. Anyhow, the other sites mentioned in the digital transmissions pretty much nail it as SEC, based in Crewe.