SDRTrunk - need advice

[royldean]

I've got the latest SDRTrunk and voice decoder installed (ubuntu 18.04). Trying to monitor this system:

Montgomery County (P25) Trunking System, Eagleville, Pennsylvania - Scanner Frequencies

The control channel is very strong (I'm listening to west simulcast). Should I be using "Phase I" decoder with LSM selected, or "Phase II" decoder?

If I use "Phase II", I get some activity in the messages area - "sync loss - bits processed [6000]"
If I use "Phase I", I get tons of activity in the messages are like this:

2020:01:21 20:05:05

APCO-25

0

NAC:1635 TSBK2 SEC_CCH_BROADCST RFSS:1 SITE:3 CHAN A:0-391 SERVICE OPTIONS:[BACKUP CONTROL CHANNEL] CHAN B:0-181 SERVICE OPTIONS:[BACKUP CONTROL CHANNEL]

But I never hear any voice or see any additional channels popping up in the channel area. I should note that this system is being tested, so it could be that there is simply nobody transmitting at the times I am looking.

But first things first, I've read that trunked PII systems should be decoded with the PI decoder.... and it seems that I get "better" results that way. Is that correct? Any other advice? Thanks.

 

[simmsrep]

I've read that trunked PII systems should be decoded with the PI decoder

Yes, that is correct. Also make sure you have the jmbe library correctly configured or you wont get any audio.

 

[DRL-XM43]

I've got the latest SDRTrunk and voice decoder installed (ubuntu 18.04). Trying to monitor this system:

Montgomery County (P25) Trunking System, Eagleville, Pennsylvania - Scanner Frequencies

The control channel is very strong (I'm listening to west simulcast). Should I be using "Phase I" decoder with LSM selected, or "Phase II" decoder?

If I use "Phase II", I get some activity in the messages area - "sync loss - bits processed [6000]"
If I use "Phase I", I get tons of activity in the messages are like this:

2020:01:21 20:05:05

APCO-25

0

NAC:1635 TSBK2 SEC_CCH_BROADCST RFSS:1 SITE:3 CHAN A:0-391 SERVICE OPTIONS:[BACKUP CONTROL CHANNEL] CHAN B:0-181 SERVICE OPTIONS:[BACKUP CONTROL CHANNEL]

But I never hear any voice or see any additional channels popping up in the channel area. I should note that this system is being tested, so it could be that there is simply nobody transmitting at the times I am looking.

But first things first, I've read that trunked PII systems should be decoded with the PI decoder.... and it seems that I get "better" results that way. Is that correct? Any other advice? Thanks.

Yes a P25 phase ! or II trunk control frequency is to use Phase I decoder.

The Phase II decoder is used for only single, non control P25 phase II signals.

 

[royldean]

Thanks! Follow up: I've followed the JMBE install directions and I believe it's installed correctly. Is there any way to verify other than hearing audio? I'm assuming that if a new channel "pops up" it should indicate that it's voice, no? I guess I'll need to to test it on a system that actually sees significant traffic.

 

[simmsrep]

Under "now playing screen" and then the "events screen" when I get voice I see under the event tab "Group call" and under the detail tab I see "Phase 1 channel grant". If the call is encrypted it will show "Phase 1 channel grant encrypted circuit" which will automatically mute the call.

 

[simmsrep]

You can also join sdrtrunk in google groups. There is a lot of discussion going on there and you would probably get a better response to your questions there. The developer monitors this group and frequently offers advice.

 

[DRL-XM43]

You can also join sdrtrunk in google groups. There is a lot of discussion going on there and you would probably get a better response to your questions there. The developer monitors this group and frequently offers advice.

That is the best way to get support for SDRTrunk

Redirecting to Google Groups

 

[royldean]

Thanks, all. I will join the group.

 

[royldean]

Update (and to close out thread), I brought my lappy top into work (One county south of where I was originally testing) and they are running a full time P25PII system here. I can confirm that SDRTrunk is working just fine and decoding voice (although many missed transmissions because I am only using a single dongle and some of the trunking frequencies are out of range). Nice!

Thanks, everybody!