OP25 Nightmare

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Shawnjnorton

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Ok, so I have tried setting up op25 about 6 times with no luck. Is there any updated install instructions like step by step. I'm good at linux but not great. Just wanna listen to the P25 phase 2 system out here. I know all my equipment is right. Also is it even possible to install in virtual box with no issues? Just extremely lost here. Oh and the system is Bucks County Public Safety Network in PA. Really appreciate any help.

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boatbod

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Mar 3, 2007
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Talbot Co, MD
Ok, so I have tried setting up op25 about 6 times with no luck. Is there any updated install instructions like step by step. I'm good at linux but not great. Just wanna listen to the P25 phase 2 system out here. I know all my equipment is right. Also is it even possible to install in virtual box with no issues? Just extremely lost here. Oh and the system is Bucks County Public Safety Network in PA. Really appreciate any help.

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I presume you mean this system?
https://www.radioreference.com/apps/db/?sid=7699

How far have you got with setup? Post your op25 startup script and trunk.tsv contents and I'll take a look.
 

boatbod

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Assuming you have a working Linux distro.

Step 1 : download, build and install op25
Code:
sudo apt-get install git
cd ~
git clone https://github.com/boatbod/op25
cd ~/op25
./install.sh

Step 2 : Create and install config files (I can assist with this)

Step 3 : Get the driver and application working. Here are instructions I sent to another user who was going through similar setup steps.
1. First we're going to check the device driver is install and working correctly.
Plug the RTL device and in a command window type "lsusb". You should see something that says "Realtek Semiconductor Corp." or similar.

2. Next it's helpful to see if the rtl driver can successfully be opened. I like to use the "osmocom_fft" utility for that. Simply run the command and if a gui window pops up life is good. If the window does not appear, there may be a problem with blacklisting. Close the window before moving on to the next step.

3. Now it's time to try running op25. You'll want at least two terminal sessions open.
In the first terminal window, run the following commands:
cd ~/op25/op25/gr-op25_repeater/apps
./op25.sh
In the second terminal window, run the following commands:
cd ~/op25/op25/gr-op25_repeater/apps
tail -f stderr.2

4. At this point you should have a scrolling log in one terminal and the op25 app in the other. In an ideal world, the op25 screen would have a rolling "tsbks" counter in the top right hand side. More likely the counter will be stuck at 0, which means we need to tweak the tuning to dial in things like PPM error correction and fine tuning.

5. In the op25 screen, press the "1" key and a window should pop up with the FFT plot showing the control channel signal somewhere near the center. Your task is going to be to dial in the ppm error correction (-q parameter in op25.sh) so that the peak coincides with the vertical tuning line. Use positive or negative values of "-q ##" to make the correction in the startup script file op25.sh.

6. When the tuning is close, you can make fine adjustments using the ',' and '.' keys in the op25 window. There's a bit of a lag, but you should see the number in parenthesis (after "frequency") go up or down by +/-100. Typically if PPM is correct, you'll not need more than about +/- 350 fine tune. You can switch to plot "5" (mixer) to more accurately make the fine tuning adjustments. The goal is a symmetrical hump with closest to 0 "Mixer: balance" shown at the top of the plot screen.

7. At this point you should have a rolling tsbk counter and hopefully be receiving audio. If not, let me know what's going on with screen shots and copies of the stderr.2 log and I will try to help further.
 

Shawnjnorton

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Apr 22, 2012
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Bucks County, PA
I also believe I have op25 built and installed. I followed the first step above with no issue. I have config files that I believe are setup right but unsure how to install them?

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Bill88

Longtime Member
Joined
Jul 6, 2007
Messages
126
Location
Grovers Mill, NJ
It does with no problem


Once you have the software installed and the dongle plugged in and configured, go to the
~/op25/op25/gr-op25_repeater/apps
directory and execute the file ./op25.sh.

That should bring up a text based terminal that allows you to interact with the op25 application and adjust the tuning to lock on to the control channel.
 
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