op25-dev

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308 discussions

by Alex alex323＠gmail.com [op25-dev]

Hello, Let's say you're scanning the airwaves in the frequency range of a known P25 system and come across a spike in power at one particular band that never shuts off. * You should think that you've located a control channel, correct? * If so, is it safe to say that the upstream and downstream channels are side-by-side (one contiguous frequency band)? * What is the most accurate way of determining whether what you've discovered is a Phase I or Phase II system? * When someone keys up a radio, is the following sequence of events accurate?: 1. The radio sends a packet via the upstream control channel indicating that it wishes to speak. 2. The fixed site sends a packet via the downstream control channel indicating a frequency X on which it wants the speaker to transmit. 3. The fixed site sends a packet via the downstream control channel instructing all radios in the talk group to tune in to a frequency Y. 4. The speaker transmits on frequency X, and the fixed site acts as a repeater, re-broadcasting the audio to frequency Y. -- Alex

8 years, 3 months

wireshark UDP output

by russ.innes＠gmail.com [op25-dev]

I seem to be having no luck getting the wireshark output to work monitoring a P25p1 system. I have enabled it ( -w) and verified that scope.py is loading the p25_decoder object in which the wireshark flag and port are passed to.. however if I use nc or a python script to listen on 23456 (or wireshark) I'm not getting a thing.... any thoughts? Cheers

8 years, 4 months

New Install, RTL Dongle only allows spectrum analyzer view

by kd8b＠thebades.net [op25-dev]

I am not sure if I set something wrong or this is a limit of the device. I built a new linux box and installed op25 as suggested on the page of http://op25.osmocom.org/trac/prefs/wiki/InstallInstructionsPage http://op25.osmocom.org/trac/prefs/wiki/InstallInstructionsPage I blacklisted the dvb_usb_rtl28xxu kernel module as it was interfering when I tried to run the scope. When I run the RTL scope command from http://op25.osmocom.org/trac/login/wiki/SignalScopePage http://op25.osmocom.org/trac/login/wiki/SignalScopePage, ./scope.py --args 'rtl' -g 65 -f 123.45e6 -N 'LNA:49' -V -v 0 -S 1000000 -q 39 -T trunk.tsv I change the -f freq to my freq of interest and the scope runs but it appears to be in a locked read only type state. I can view the spectrum analyzer but I can change nothing in that panel. Everything is sort of greyed out. I tried not loading the -T trunked part of the command as I am looking at a conventional channel right now. I tried to see if I could find anything in the internet on this as well as here but not finding anything. If I run the command as a discriminator scanner installation, the scope module is not locked and I can connect other screens like c4fm, constellation etc... Is this a limit of the RTL device or did I overlook something?? I have been trying on and off over last couple years to get OP25 working and my Linux skills have been improving in that time but not sure what this is caused by .. Doug

8 years, 4 months

Phase 2 Audio quality [2 Attachments]

by lukekb＠gmail.com [op25-dev]

I have the Phase 2 working, which is pretty exciting! The sound quality is generally intelligible, but not the best. I was wondering if that is just the nature of Phase 2 or if I have something configured wrong. It sort of sounds like the people are speaking through a Kazoo. A bunch of it is online here: https://openmhz.com/pgcnorth https://openmhz.com/pgcnorth And I have a attached a couple samples. Are other folks getting better decodes? - Luke

8 years, 4 months

OP25 and GRC

by r_johnson2020＠yahoo.com [op25-dev]

Hello, Regarding Balint's newer (2016 version) OP25 flowgraph for GRC, has anyone been sucessful in getting it to work yet? I see that there is a recent thread here regarding OP25 command line version from op25.osmocom.org/trac/wiki. I've been able to get that version working on the command line. No problems there. But when it comes to running the OP25 flowgraph in GRC, well, it seems to require some black magic to get it to work (I've heard rumors of a few people getting it to work, but unverified). The command line version is great and works wonderfully, but it doesn't really teach us much about the inner workings of DSP and P25. I'm running a dedicated Ubuntu 14.04 machine. I installed OP25, GNU Radio etc verbatim from the install instructions on the OP25 install page. Every thing surprisingly went well. Regarding Balint's flowgraph, I can get the flowgraph to compile and run. I set the center frequency to the frequency I'm transmitting on. All the graphs and scopes seem to functioning correctly. They show a signal being received (from my transmitter), but it just can't seem to get around to decoding the P25 signal. I know that gnuradio-companion (GRC) and flowgraphs aren't technically a part of the OP25 project, but I thought someone else here may have fiddled with it and got it to work. I've been trying on and off for several days without success. http://wiki.spench.net/wiki/Gr-baz#op25 http://wiki.spench.net/wiki/Gr-baz#op25 https://github.com/balint256/gr-baz https://github.com/balint256/gr-baz Here are the links to Balint's wiki and git page if anyone cares to play around with it. I believe the wiki page still contains the outdated (2013) version of the flowgraph, whereas the example at the git page was updated in late 2015 for GNU Radio v3.7.

8 years, 4 months

OP25 digital voice for dmr/dstar/p25/ysf

by ikj1234i＠yahoo.com [op25-dev]

The OP25 Group in 2009/2010 added a software TX for P25 FDMA which was based on the fullrate MBE codec contribution made by Pavel Yazev. Today with the addition of a halfrate encoder we announce a software TX for two amateur radio digital voice modes (dstar and ysf) as well as 2-slot DMR Base Station support in addition to the existing P25 TX. The ysf support includes both halfrate and fullrate voice modes. At this time my impression of the voice quality is very good to excellent in all modes except dstar where it may be considered only fair; we believe the issues with the dstar codec will be very amenable to improvement over time. The software has been tested successfully using a PC+soundcard connected to an Icom IC-820H via the high-speed (packet 9,600 data input) connector in the back of the radio. Support for SDR TX devices such as the hackrf and usrp will be added at some point. To get started, clone the repo, checkout the 'max' branch, and open the doc html file in your browser: git clone https://git.osmocom.org/op25 cd op25 git checkout max Then use your favorite web browser to view the file op25/gr-op25_repeater/apps/tx/doc.html within the repo. 73 Max

8 years, 4 months

New member question

by Chuck Kelsey wb2edv＠roadrunner.com [op25-dev]

Hello all. I am new on this list as of Thursday, so hopefully I'm not asking something that has been covered a bunch of times. I did try a search first on the web page. Anyway, I'm interested in finding how to use OP25 to listen to our new county P25 phase 2 simulcast system. I've listened to the system with a scanner and the results were pretty dismal. Some have told me that OP25 puts the scanners to shame. I understand that OP25 works on Linux, but not sure of system requirements. I believe I read that a Raspberry Pi3 won't cut it. While I use a Linux machine for AllStar, I don't really know much about the operating system (someone provided me with an image on a disk that self-loaded). So, please keep it simple. Chuck WB2EDV

8 years, 4 months

lfsr module missing

by 'lists＠lazygranch.com' lists＠lazygranch.com [op25-dev]

opensuse 42.2 /usr/local/src/op25/op25/gr-op25_repeater/apps/scope.py -f 475000000 -s 80000000 Traceback (most recent call last): File "/usr/local/src/op25/op25/gr-op25_repeater/apps/scope.py", line 59, in <module> import trunking File "/usr/local/src/op25/op25/gr-op25_repeater/apps/trunking.py", line 26, in <module> import lfsr ImportError: No module named lfsr However it appears to be there: /usr/local/src/op25/op25/gr-op25_repeater/apps/tdma/lfsr.py

8 years, 4 months

Decode with AMBE3000 chip?

by Tom Hayward tom＠tomh.us [op25-dev]

I have a ThumbDV here, which is an AMBE3000 chip mounted to a board with USB interface. http://nwdigitalradio.com/wp-content/uploads/2012/04/ThumbDV-A.pdf On the computer, it is accessed with a serial interface, or let their ambeserver software handle the serial and communicate with ambeserver over the network. http://nwdigitalradio.com/dv3000-ambeserver/ Has anyone tried integrating this with OP25? The primary system I monitor is P25p2 (TDMA), but I am curious about DMR and Dstar as well. My goal is to offload voice decoding to this hardware for CPU savings so that lower power systems can be supported. I am also curious if it will improve voice quality, but this is secondary to CPU savings. Has anyone profiled OP25 to see where the CPU usage goes? I'm curious how much I could really reduce it by offloading voice decoding but not RF demodulation. I suspect it's working pretty hard on RF demod. If no one has tried this, can someone at least point me toward the right part of the code to inject support for alternative decoders? Tom

8 years, 5 months

op25 scope.py issue

by lists＠lazygranch.com [op25-dev]

I built gnuradio from source. It passes the "make test". uname -a Linux linux.suse 4.4.49-16-default #1 SMP Sun Feb 19 17:40:35 UTC 2017 (70e9954) x86_64 x86_64 x86_64 GNU/Linux I'm using the KDE Plasma desktop. I can set the gtk2 theme to whatever the developers prefer. ------------------------------------------------------------------------------------ When run as root: linux:/usr/local/src/op25/op25/gr-op25_repeater/apps # ./scope.py osmosdr source_c creation failure Traceback (most recent call last): File "./scope.py", line 2751, in <module> app = stdgui2.stdapp(p25_rx_block, "APCO P25 Receiver", 3) File "/usr/local/lib64/python2.7/site-packages/gnuradio/wxgui/stdgui2.py", line 46, in __init__ wx.App.__init__ (self, redirect=False) File "/usr/lib64/python2.7/site-packages/wx-3.0-gtk2/wx/_core.py", line 8628, in __init__ self._BootstrapApp() File "/usr/lib64/python2.7/site-packages/wx-3.0-gtk2/wx/_core.py", line 8196, in _BootstrapApp return _core_.PyApp__BootstrapApp(*args, **kwargs) File "/usr/local/lib64/python2.7/site-packages/gnuradio/wxgui/stdgui2.py", line 49, in OnInit frame = stdframe (self.top_block_maker, self.title, self._nstatus) File "/usr/local/lib64/python2.7/site-packages/gnuradio/wxgui/stdgui2.py", line 76, in __init__ self.panel = stdpanel (self, self, top_block_maker) File "/usr/local/lib64/python2.7/site-packages/gnuradio/wxgui/stdgui2.py", line 98, in __init__ self.top_block = top_block_maker (frame, self, vbox, sys.argv) File "./scope.py", line 156, in __init__ gain_names = self.src.get_gain_names() AttributeError: 'NoneType' object has no attribute 'get_gain_names' --------------------------------------------------------------------------------------------------------- When run as a user: g@linux:~> /usr/local/src/op25/op25/gr-op25_repeater/apps/scope.py Traceback (most recent call last): File "/usr/local/src/op25/op25/gr-op25_repeater/apps/scope.py", line 59, in <module> import trunking File "/usr/local/src/op25/op25/gr-op25_repeater/apps/trunking.py", line 26, in <module> import lfsr ImportError: No module named lfsr

8 years, 5 months

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