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Install scripts for some packet functionality


This repository contains scripts & notes for taking a Linux Raspbian distribution and creating a working image that will run packet, HF programs or both. The NWDR image has already installed a number of popular programs so that ONLY configuration is required.

  • Since the sound CODEC is a stereo device there are 2 audio channels that may be split between packet & HF program usage.

HF Program configuration

Packet Configurations:

  • Core only: This includes direwolf & AX.25 with no other application running.

  • Linux RMS Gateway for Winlink

  • Winlink client: paclink-unix in two flavors

    • paclink-unix min which installs postfix and a console base email client.
    • paclink-unix default which allows using any e-mail client that supports IMAP.
  • APRS client: Xastir, YAAC, nixtracker

  • APRS digipeater & iGate: aprx

Both HF programs & Packet at the same time

  • Split channel scripts control configuring the audio CODEC channels.

Configuration scripts

The NWDR image has installed all software listed here

Note: These configuration scripts were meant to be run once only starting from a clean image. They might work if used more than once but they were not tested for that case. If an installation fails I would like to know about it. Please post any problems you might have on the UDRC forum.

Whether using HF programs or packet you MUST set deviation using ALSA settings for your specific radio. draws-manager and script help determine these settings. Usually for a particular radio the 1200 baud & 9600 baud ALSA settings will be different.

As of around August 2019 main line Linux kernel has a driver for the Texas Instruments tlv320aic32x4 DSP sound chip that can be used by UDRC/DRAWS HAT.

The NW Digital Radio UDRC II or DRAWS are HATS that contains the tlv320aic32x4 DSP sound chip plus routes GPIO pins to control PTT. They also have a 12V to 5V buck regulator so that you can run the Pi with the HAT from a 12V supply. DRAWS also has a SkyTraq S1216F8-GL GNSS GPS Module and an TI TLA2024 4 channel A/D converter accessed by the 8 pin Auxiliary connector.

  • For packet, only the direwolf configuration is specific to the UDRC II or DRAWS hardware.

  • For HF programs, you must use the proper sound card device name for both Capture and Playback devices.

    • Each HF program may have a different syntax for referencing the device, for example:
udrc: - (hw:0,0)


output: plughw:CARD=udrc,DEV=0


Regardless of what functionality you want to install the first thing to run is which will do the initial configuring of the Raspbian kernel & install AX.25 & direwolf.

Core is required for all packet apps using a UDRC or DRAWS HAT. This option installs direwolf & AX.25 tools/apps/library. Use this option if you want to run APRS or some packet client that uses direwolf or AX.25. As part of the core requirements this option also configures systemd to start direwolf, AX.25 attach & AX.25 apps like mheardd at boot time.

Packet App Configuration

RMS Gateway

In order to install the Linux RMS Gateway you must register with Winlink to get a password for a gateway.

See for details on installing RMS Gateway functionality.


  • Installation options
  • paclink-unix will work with any Linux email client that supports IMAP for retrieving email messages
3 email clients supported with install scripts



  • Script that generates a tone file using sox, turns on correct PTT gpio and plays wave file through a UDRC II or DRAWS HAT.
  • Generating a tone sine wave is one part of measuring deviation. The other part is doing the actual measurement. The Xastir wiki has a nice article on how to do that using an RTL SDR dongle.
  • systemd service file supplied by Ken Koster N7IPB.



Config scripts, systemd files & other miscellaneous files






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