[op25-dev] OP25 for noobs by a noob (long)

'WA8WG' wa8wg@centurytel.net [op25-dev] op25-dev at yahoogroups.com
Thu Aug 3 22:40:19 UTC 2017



I may be able to help if you could post your scope.py and trunk.tsv files along with a full description of the particular P25 system that you are trying to monitor.  I can also help you with getting GNU Radio + OP25 working properly in Virtual Box under Windows.   I am not well versed with hackrf but have learned a number of things using the RTL-SDR that might apply to your situation.  Feel free to email me directly if you’d like.


Best regards,




William G. Becks, WA8WG

N7027 Shady Lane Circle

Porterfield, WI 54159


Email:  <mailto:wa8wg at centurytel.net> wa8wg at centurytel.net


From: op25-dev at yahoogroups.com [mailto:op25-dev at yahoogroups.com] 
Sent: Thursday, August 3, 2017 9:49 AM
To: op25-dev at yahoogroups.com
Subject: Re: [op25-dev] OP25 for noobs by a noob (long)



Good Day FM

     What I have done is a lot of reading, reviewing, relearning and drinking to attempt to get this working. It's a challenge for sure.

I have taken your procedure and added the installation of Gqrx along with what is needed to get my hackrf one setup and working.

I have three laptops that I've loaded and tried to get working as well. The laptops were Dell's and one Gateway. The selection was

based on the statement regarding hardware requirments on the op25 development pages which called for a medium performace 

computer. My first Dell was a single core with hyperthreading capabilities giving me two cores. The USB ports were both versions

1 and 2. With the Gqrx utility, I had to really trip overhead operations down just to receive mono fm radio. Never had anything come

out from the op25 even turning off all but the scope display off. I tried the Gateway, which gave me four cores to use and USB 2 ports.

The Gqrx was still choppy and still nothing from the op25. My last Dell is also a quad core and usb 2 and 3 versions. Gqrx ran like

a champ on both mono and stereo fm reception, but still nothing from the op25. I have gone one more step and that is to load this on

my work computer under virtualbox. I've dedicated two cores from my four core system to this along with usb version 2 emulation. I 

get choppy Gqrx only in mono fm and I've gotten some really choppy op25 demod to come out, but not legible. Another challenge was

to fix one of the warnings that I was getting regarding the 'buf' variable in the code as well. What would be great is if I could get a test

file for both the phase 1 and 2 so that I could at least validate that the software has been loaded and configured correctly and that it's working and then i could focus on the hackrf to see if I'm missing some configuration on that. I have even set my op25 scanner next

to my laptop to see if it picks up and broadcast that has come over. The control channel is received with some of the voice channels but no audio. I have an external antenna as well and am only about 10 miles from the main antenna. I think I've covered everything, hope to get some sample files to continue with. Have a great day and thank you again.


Happy Trails




From: "flkmrz at gmail.com [op25-dev] <mailto:flkmrz at gmail.com%20[op25-dev]> " <op25-dev at yahoogroups.com>
To: op25-dev at yahoogroups.com 
Sent: Wednesday, July 26, 2017 11:28 PM
Subject: Re: [op25-dev] OP25 for noobs by a noob (long)



Hi Dick,

You're welcome. Happy to help.

As far as a grc file goes, I've been working on that off and on lately.  Been busy though, so I haven't had the chance to get it working yet.

Ideally, what I would like to do is be able to generate a stand-alone op25 file that would run on lightweight systems, such as nextthing's chip, rasberry pi, etc. and not require a ridiculously complex install procedure.

There are a number of grc files floating around for op25 -- the problem is that none of them work. It appears that the main issue with these is that they either reference gnuradio blocks that have been deprecated, or gnuradio blocks that have been forked.  Either way, grc simply errors out and won't work.

So, what needs to happen is to track down the source code for the required blocks, build them, and integrate them into gnuradio.  Then, put together a functional op25 grc file. Unfortunately, this seems to be a non-trivial task. Ideally, this would then be added to the mainline trunk version.

As far as audio goes, there are several threads on the forum dealing with audio issues.  Come back and let us know what you did to get your audio working.




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