What is this?

[commscanaus]

Hello All,

This system? appeared just very recently on a 470Mhz channel, which has good signal strength to my location.
It sounds like an idle EDACS 9.6Kbps control channel, then what sounds like some sort of digital modulation interrupts the data stream. I have not heard this sort of modulation before.
We have EDACS analogue trunking @ 800Mhz used here locally, but this seems to only use one channel pair- with the input 5.2Mhz above the output.

I apologize if posting an attatchment is against the group rules- but it is the only way I can properly illustrate what I am hearing.

Is this Provoice or Aegis?

I have tried programming my UBCD396T with this frequency as an EDACS SCAT system which results in the control channel muting and only the digital bursts passing through the speaker. Interestingly, no talkgroup info is displayed. If there is only one group of users- then what is the purpose of the control channel? - assuming that is what is being transmitted.

There is no expectation that I can decode the voice- encrypted or otherwise.

Thanks, Commscanaus!

 

[morganAL]

A SCAT site running mobile data? At least that is what it sounds like. That would explain why your scanner does not decode TG info. A lot of mobile data apps that run on EDACS do I-calls for data instead of group data calls.

 

[bassmkenk2508]

That "data interruption" is definitely a ProVoice transmission. And, yea, by the sound of it, it is a SCAT site.

It is not neccessarily "one" group of users... can be two three or whatever number of groups. But they just cant transmit at the same time. They will get a busy signal if they try to.

 

[commscanaus]

Thanks very much for the replies!

I had suspected a data transmission- as used by mobile terminals.

Voice transmssions are what I really think this is- and the channel is busy 24hrs 7 days, so it is probably a security company. I agree with bassmkenk2508- a SCAT site running Provoice. This is the first of such protocols to be used locally and would not be surprised if it takes over from the analogue EDACS systems we have on 800Mhz eventually.

Perhaps we could see Opensky used here as well? Motorola are promoting and trialling a TETRA network on 800Mhz now.

Regards, Commscanaus.

 

[ECGBaritoneMastr]

Hey. I've heard this before, but very rarely on our local EDACS system. So, what exactly is ProVoice?

 

[bassmkenk2508]

it is M/A-COM's proprietary digital voice transmission. No scanner can track the transmission or decode it into audible voice.

You may think of it as P25 's little, evil cousin... lol (b/c we can listen in on P25, but not ProVoice :lol: ). I do at least.

For more ProVoice info, see this wiki link: http://wiki.radioreference.com/index.php/EDACS_Provoice or search/browse the M/A-COM forum.