Important: Use only Compass Linux images and dstarrepeater packages.
They contain support specific to the UDRC™. Source is available
for review on GitHub.
Mount your UDRC™ on a Raspberry Pi 2 or 3
Make sure the pins are
properly aligned and use the supplied standoffs to support the
board above the HDMI port.
Digital Radio Controller
If you are a local simplex node or using a personal callsign, do not register at ircDDB.net use QuadNet instead. If you want to use your personal call sign, you will be able to run the repeater and perform linking to repeaters and reflectors, but will be unable to do callsign routing including STARnet Digital groups.
If you are running a repeater, and haven't previously registered at ircDDB, now is a good time to register
unique callsign for your repeater at
. In the United States
this needs to be a club callsign, in other countries a secondary
callsign is necessary. If you already have an ircddbgateway
registered, you can just add this repeater to it at configuration.
Create the Boot Image
Obtain a high quality microSD card. A Class-10 card of
8GB or more is recommended.
- Download a Compass Linux image from archive.compasslinux.org
The 'lite' version is without a GUI and will require hand
editing of the dstarrepeater configuration file. The full
version has graphic configuration tools for those new to setting up
dstarrepeater and ircddbgateway.
Unzip and copy the uncompressed image to the SD card using the
procedure outlined on the Raspberry Pi site.
Boot for the First Time
- Place the microSD card in the Raspberry Pi.
- Attach a monitor and keyboard/mouse to the Raspberry Pi
- Attach Ethernet via the RJ-45 jack to your network.
Apply power using the microUSB port next to the HDMI port (good if
you are not at the repeater site)
- Allow the Raspberry Pi to boot up
Login (User: pi,
From a terminal command line, verify that the UDRC™ is
recognized by typing the command
(that's a lowercase l) and observe that udrc is listed as a
card. If you do not see it listed, power down and remount the
Perform any Linux configuration specific to your installation,
e.g. assign specific network addresses, install favorite tools, etc.
(This is beyond the scope of NW Digital Radio support, please use
Linux support resources for assistance.)
Note: DO NOT RUN raspi-update - it will break your install
You may wish to edit the /etc/hosts file
and add reference to the hostname, for example if you keep the default
'compass' hostname, add a line
To preset the pins and levels on the UDRC™ we provide a
script. Execute the following:
https://goo.gl/7rXUFJ | sudo sh
'pipe' or | is usually above the \ key on most keyboards -- if you
want to see what the script does, leave off '| sudo sh')
To gracefully shutdown the Raspberry Pi, you may use the
command sudo halt
Make sure the UDRC™ is
connected to the radio or repeater via Mini-DIN 6 port.
NOTE: Many standard Mini-DIN 6
cables, e.g. PS2 cables, do not have all of the pins wired and will
not work! Be sure your cable has all 6 pins wired straight
through. If you obtained the cable from NW Digital Radio it will
have all pins wired.
to the Raspberry Pi
Download the seed file for the dstarrepeater
sudo curl -L -s -o /etc/opendv/dstarrepeater_1 https://goo.gl/owjCLU
If using the GUI install, you can edit the file with:
sudo -E dstarrepeaterconfig 1
If non-GUI, use an editor like nano or vi to edit, e.g.
sudo nano /etc/opendv/dstarrepeater_1
You will need to change the repeater callsign and gateway callsign to your system. If you are doing a 70cm repeater these are the only settings
that need changed for initial configuration. Only adjust other settings if you understand their effect.
In /etc/opendv/dstarrepeater_1 edit:
Set serialConfig to
serialConfig 5# For simplex access points (hotspots) and non DR-1X repeaters attached to the Mini DIN-6 connector
Set mode for simplex
Once configured, issue the command:
sudo systemctl start dstarrepeaterd@1
you want to see a GUI, run the commands:
sudo systemctl stop dstarrepeaterd@1
sudo dstarrepeater 1
The UDRC™ should now decode D-STAR signals received on the radio or
repeater's input. Test by keying up and watching the display on the
you want the dstarrepeaterd daemon to start on reboot, issue the
sudo systemctl enabledstarrepeaterd@1
A video of hints for management of the
for troubleshooting are at /var/log/opendv
Each radio and repeater model may need adjustments to the standard configuration. The items that may need adjustment are as follows:
- Under dstarrepeater config in modem sound card, make sure both TX and RX sound cards are set to udrc
- Also you may need to adjust TX and RX invert based on the radio and band.
- Modulation level is set using using the program alsamixer, select the udrc, adjust LO first and then PCM to get the right deviation
- Detection level is set in alsamixer with the ADC setting
The "poor man's" approach to getting this working. (Without a deviation meter and spectrum analyzer.)
Use a second FM receiver and listen to the transmissions. You should hear modem tones on each transmission,
assuming you are using a simplex frequency (DUPLEX offset 0.0), for both your D-STAR radio and the radio or repeater.
Listen to the relative volume of the two transmissions. Is the radio or repeater is 'louder' or 'quieter' than the D-STAR radio?
If it is louder then you need to decrease the drive of the modem out of the UDRC, if it's quieter, then you need to increase it.
If they are the same, then you need to adjust the TX polarity in modem setup (via dstarrepeaterconfig 1)
If the radio is keying but no tones, check the 'Sound Card' settings in dstarrepeaterconfig 1 -- make sure both TX and RX are set to udrc.
How do you change the drive level, you ask? Glad you asked.
You need to open a terminal and run the program alsamixer and press 'F6' key to switch to the udrc. See here fo keyboard commands.
There are two controls that adjust the level of the modulation. One titled PCM (on the far left) and one titled LO which is almost
all the way to the far right (use the right arrow key to get to it). Start with the LO level, take it up or down (louder or quieter) to
see if you get the output level right. If that doesn't get you there, you may need to fine tune with PCM.
When you get it just right, look at the upper left of the screen and note the level in 'dB' for PCM and LO. You can use those numbers to
modify a script to reset the modem to those values in the future.
Note: if you do not hear any audio on the FM radio when the UDRC™ is transmitting, make sure LOL is not muted in alsamixer.
When you get it right, press the ESC key and give the command
sudo alsactl store
You can create your own script by saving the default script
curl -L -s https://goo.gl/7rXUFJ ~/my-setup-script.sh
chmod +x ~/my-setup-script.sh
Edit the script changing the values for PCM, LO, and ADC according to what you found in alsamixer setup.
You can then use the script to reset values when needed.
there are no special instructions for ircDDBGateway for the UDRC™,
please refer to the documentation in the files section of the Yahoo
you would like a web based dashboard for ircDDBGateway, check out the
real time dashboard at
Digital Radio is in the process of setting up various community groups
at Groups.io Please create a
account at Groups.io
the main NW Digital group by sending an email from your registered
email account to
then send an email to
use the group for questions and to share your experiences, so that all
UDRC™ users can benefit from the replies.