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Digital Voice for Amateur Use - Discuss use of digital voice technologies on the amateur radio bands. This is to include technologies such as VoIP, P25, DMR/TRBO, NXDN, D-STAR, etc.

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Old 03-22-2017, 9:50 AM
  Amateur Radio Operator
Amateur Radio
Join Date: Aug 2008
Posts: 428
Default OP25 digital voice for dmr/dstar/p25/ysf

FYI This announcement appeared in the op25-dev yahoo group today...

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 an enhanced 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
cd op25
git checkout max
Then use your favorite web browser to view the file
within the repo.


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  #2 (permalink)  
Old 01-01-2018, 3:50 PM
  Amateur Radio Operator
Amateur Radio
Join Date: Apr 2003
Location: Green Bay, WI
Posts: 97

For those interested this was posted this a few days ago to op25-dev:


1) New Web site
Our new web site is now on the air! I'd like to thank Matt Ames for
his efforts and hard work in reworking content to fit the new format.

I'd also like to take this opportunity to thank our hosts at Osmocom,
Harald and Holger, for kindly offering this free resource and home for
the project.

web site: WikiStart - OP25 - Open Source Mobile Communications
git repo:

2) Recent additions and updates
Several updates have recently been pushed and are in the 'max' branch
of the repo. In addition to bug fixes in both transmitter and receiver
applications and libraries, there are a couple of new features:
* remote terminal: the curses terminal may now run in a separate process
or on a separate machine from, with connectivity via UDP.
* dstar transmitter configuration: the dstar specific config options for
repeater 1/2, mycall, and urcall are now supported.

3) CPU usage reduction effort
Except for the actual speech decoding process which remains unchanged,
the channel tuning and demodulation logic has undergone some streamlining.
The result should be a significant reduction in CPU usage in,
especially during idle periods. It's possible some of these optimizations
may be slightly too radical; it would be good to receive feedback from all
users, but especially from those with-
* crowded bands with close channel spacing
* p25 phase 2/tdma talkgroups
* "center frequency" set to zero in the trunking tsv file

4) New multiple rx app
Released today (Dec. 25, 2017) is a sneak preview of a new receiver app, It should be considered alpha test grade. The highlights:
* receives DMR/YSF/P25(P1) (DSTAR almost finished)
* an arbitrary number of concurrently active SDR devices
* arbitrary numbers of channels/frequencies
For more information see the README file in the apps/ directory of the repo.

All of these additions have been pushed to the 'max' branch of the repo.
If you have a previous installation of OP25 you should change to the 'build'
directory of that installation and do
sudo make uninstall
prior to pulling and building the new version.
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