APRS - Amateur Position Reporting System

  1. General Information
  2. How to build an APRS Digipeater and IGate
  3. Direwolf
  4. RPi NTP Server
  5. TAPR Archive
  6. TinyTrak3 - APRS GPS Position Encoder
  7. PIC based APRS Kits
  8. HAB - High Altitude Baloons
  9. APRS Frequencies
  10. Satellite APRS

General Information

Source: aprs.fi - The APRS map (local)

Visit the live APRS Mapping solution here: The APRS Map (aprs.fi)

General information about APRS:

Two reference site for APRS are the Official Australian site and, of course, Wikipedia. The links are:
www.aprs.net.au - The Official Australian APRS Website
Wikipedia - Automatic Packet Reporting System


How to build an APRS Digipeater and IGate

How to build an APRS Reporter and iGate:
Raspberry Pi Packet TNC, APRS Digipeater, IGate Raspberry Pi Packet TNC, APRS Digipeater, IGate (local)

A pre-built raspberry pi image for using an rtl-sdr as an aprs rx IGate


Setting up an APRS RX only iGate using a Raspberry Pi, RTL-SDR Dongle and a Pre-Built Image

BUILD on R2 27th Janruary 2018 - (RTL-SDR.COM RTL820T2 TCXO BIAS-t HF V3):
1. Torrent download afsk-master.zip and extract aprs-igate.img
2. APRS Passcode Generator http://apps.magicbug.co.uk/passcode/index.php VK4PK Passcode: 23289
3. Run update  and upgade
4. Change Pi password
5. Run Config and Set Locals and IP address
6. edit ~/sdr.conf Set callsign and Long and Lat

APRS Reporter

This reporter uses the vox facility and is not recommended for APRS transmitter
because of the time delay of starting and finishing transmision. Super Simple APRS Position Reporter
A GPS daemon is required to read the output of an external GPS unit.
A full discusson about gpds can be found here: GPSD Client HOWTO
Below are the instruction to install gpsd on a linux system:

RPi GPIO to PPT on Tait T2000

www.marcelpost.com - GPIO pin on the RPi to trigger PTT
UV-5R PTT Interface

Using RTS signal from the PC to trigger the PTT (Tx). The computer then outputs the audio signal from the software into the mic input of the radio.

GPIO to radio via optocoupler from Sound Card Packet with AGWPE

GPIO to PPT using an optocouplier

Components for GPIO to radio via optocoupler; The ideal components for your circuit may vary because of your radio's requirements.
For example, you might be able to use a different type of IC, such as a 4N25 or PS2601,
but that may require a different value for R1.
Tait Computer Interface

Tait Front Panel RJ12 plug Interface. This replaces the microphone if the Tait is only for digital operation.
Generic PPR interface

Isolated PTT interface

Tait Front panel RJ45 Pinouts

Tait T2020 Mobile Radio Manual

How to setup the Raspberry Pi GPIO ports:

Super Simple APRS Position Reporter using a Baofeng UV-5R

This system has the problem of very slow carrier on and off because of the inherent delay results of using VOX. Raspberry Pi B+, USB GPS receiver, Baofeng UV-5R: http:midnightcheese.com/2015/12/super-simple-aprs-position-beacon - See PDF/



Direwolf is a software "soundcard" AX.25 packet modem/TNC and APRS encoder/decoder.
It can be used stand-alone to observe APRS traffic, as a tracker, digipeater,
APRStt gateway, or Internet Gateway (IGate).

Direwolf can be download here: https://github.com/wb2osz/direwolf


RPi NTP Server

Issue this command to test the Network Time Protocal:

If you do not see NTP2 then you misconfigured the pps_gpio driver. The serial time is provided to ntpd on NTP0, the PPS time is on NTP2, not on NTP1 like described earlier. So your ntp.conf will need to be adjusted. See the details below. Details about the NTP running on the Raspberry Pi single board computer can be foun here:
The Raspberry Pi as a Stratum-1 NTP Server


TAPR Archive

http://www.tapr.org/pipermail/aprssig/ - Archives to investigte


TinyTrak3 - APRS GPS Position Encoder

APRS GPS position encoder TinyTrack3 from Byonics
This is an analysis of the TinyTrack3 circuitary.
http://lms.onnocenter.or.id/wiki/index.php/TinyTrak_DK7IN http://www.byonics.com - See video


PIC based APRS Kits

PIC based APRS systems are largly depricated in favour the AR system on a borad like the Raspberry Pi.
https://www.tapr.org/kits_pic-e.html - DISCONTINUED

This site covers a collection of older APRS systems: http://www.qsl.net/ct1efl/aprs_tracker.htm - PCI-E


Softwate TNC's



HAB - High Altitude Baloons

https://makezine.com/projects/hab-aprs-tracker - See PDF


APRS Frequencies

VHF Frequencies

In Australia, a single national 2m frequency is used for APRS: 145.175 MHz
For Mobile stations, the path of APRS v WIDE1-1,WIDE2-1 is used nationally.
For Fixed stations, a path of APRS v WIDE2-1 is generally recommended.

HF APRS Frequencies

40m LSB 7035.47 7035.50 7036.00 7036.425 7036.50 7036.51 7036.515
30m USB 10148.13 10148.10 10147.60 10147.175 10147.10 10147.09 10147.075
20m USB 14100.13 14100.10 14099.60 14099.175 14099.10 14099.09 14099.075
Source: http://www.aprs.net.au/hf/hf-aprs-frequencies/


Satellite APRS

Satellite frequency generally is 145.825MHz Simplex.
To work the satellites, your path must be set to digipeat via ARISS,SGATE,WIDE2-1
Source: http://www.aprs.net.au/satellite/aprs-satellite/

Some other references about APRS via satellites …
ASTARS - APRS Satellite Traffic and Reporting System by Bob Bruninga, WB4APR
http://www.aprs.org/astars.html and, http://aprs.org/satinfo.html


Glenn Lyons VK4PK
Ver:gnl20180525 - pre published v1.0