Annoying chirp at end of (some) P25 calls using trunk-recorder

[smsscottsmith]

Ello, so this is irritating me... Here's a feed I recently put up of a single conventional P25 system. It's a Raspberry Pi and a RTLSDR using a piece of software I've otherwise not used before setting this up -> trunk-recorder

Anyone have any idea what this obnoxious "chirp" is that can be heard at the end of many (most) of the calls? I figure it's probably related to OP25 or some other portion of trunk-recorder but I have no idea where to start with diagnosing and ANNIHILATING it.

Here's the last recording at the time I wrote this post and it begins with a transmission that includes that sound.

Any and all advice appreciated. Thanks.

 

[dave3825]

Do you have a regular scanner that can receive the system? If so, is the chirp heard there? If yes, it could be MDC1200 data bursts.
If not, it could be something in Trunk Recorder. Its been a while since I ran that but I do not remember anything like that.

 

[smsscottsmith]

Do you have a regular scanner that can receive the system? If so, is the chirp heard there? If yes, it could be MDC1200 data bursts.
If not, it could be something in Trunk Recorder. Its been a while since I ran that but I do not remember anything like that.

Thanks for the response. I've listened to the raw P25 signal as well as decoded it through other means such as DSD+ Fastlane and sdr-trunk (on Windows) and have never heard such a thing. I am using trunk-recorder mainly because I saw instructions on how to set it up for the purposes of Broadcastify streaming, albeit for a trunked P25 system.

 

[dave3825]

You can try asking in the Trunk Recorder group.

Element

gitter.im

 

[smsscottsmith]

You can try asking in the Trunk Recorder group.

Element

gitter.im

HEH, clearly I am not alone. Thanks for pointing me there. I'll take some time to parse it later. Cheers.

I'll boil down my resulting findings here in a post on this thread.

 

[boatbod]

I figure it's probably related to OP25 or some other portion of trunk-recorder but I have no idea where to start with diagnosing and ANNIHILATING it.

Must be op25's fault, even though neither variant of op25 has that problem when run on their own.

While it is true that the developer of trunk recorder grabbed code from an earlier version of op25 to implement his P25 protocol handler, that does not make the application in any way related to, or dependent on op25. Both apps are open source and developers are free to reuse whatever code they deem suitable (with appropriate attribution), much like op25 itself has reused code from numerous other sources including trunk88, mmdvm, gr-smartnet, gr-fsk4, ezpwd, and so forth.

 

[slicerwizard]

much like op25 itself has reused code from numerous other sources including trunk88

What TRUNK88 code is in OP25?

 

[smsscottsmith]

What TRUNK88 code is in OP25?

Asking the important questions.

Anyways --- I have yet to dive into sifting through that link Dave posted but I will let the solution be known in this thread.

 

[dave3825]

I have yet to dive into sifting through that link Dave posted but I will let the solution be known in this thread.

You can sift if you like and possibly find someone that had the same issue but if you sign up and post and describe your problem, someone will likely respond. Its not the quickest board but those guys know trunk recorder very well.

 

[smsscottsmith]

Even with a quick glance I saw the issue I'm having strewn all over the place, HEH. It'd actually be rude to make a new thread about it...

 

[boatbod]

What TRUNK88 code is in OP25?

I used it as a reference when developing smartnet support. Curiously it seems that trunk-recorder got there first because there are strong similarities between the two in the OSW decode routines.

 

[smsscottsmith]

Even with a quick glance I saw the issue I'm having strewn all over the place, HEH. It'd actually be rude to make a new thread about it...

Element

gitter.im

 

[slicerwizard]

I used it as a reference when developing smartnet support. Curiously it seems that trunk-recorder got there first because there are strong similarities between the two in the OSW decode routines.

I don't follow. Is there a TRUNK88 that I'm unaware of that has released source code?

 

[boatbod]

I don't follow. Is there a TRUNK88 that I'm unaware of that has released source code?

Maybe I misspoke... I have sources for something most definitely smartzone related in a directory called "wtrunk" but it seems devoid of any names/copyrights showing where it came from or what it is. Dates place it circa 1999-2000.

 

[CanesFan95]

Could that be the old Windows Trunker version of the original DOS trunker? Or was that not open source?

 

[smsscottsmith]

Could that be the old Windows Trunker version of the original DOS trunker? Or was that not open source?

View attachment 126360

that's... that's a thing of beauty

 

[slicerwizard]

Maybe I misspoke... I have sources for something most definitely smartzone related in a directory called "wtrunk" but it seems devoid of any names/copyrights showing where it came from or what it is. Dates place it circa 1999-2000.

Ah, no worries. Yeah, "wtrunk" sounds like it might be "Windows Trunk(er)", but I'm not familiar with it.

 

[boatbod]

Maybe, but I've never actually run it natively, just looked through the sources.

 

[smsscottsmith]

I'm seeing mention of the issue but no solution, heh... Since I'm not even dealing with a trunked system, maybe I should just use some other software...

I attached a sample file that's been shortened and had most of the silence removed. Again - if anyone has any ideas ... I can't be the only person encountering this problem around here.

Heh... I'm used to DSD+ Fastlane which actually just sounds terrible in comparison to this but that sound is ear-blasting.

 

[smsscottsmith]

I joined their discord. Will post here if I have joy. Apparently the version in the broadcastify image is very old. So that's a starting point.