APRS (Automatic Position Reporting System) is a transmission mode which allows to exchange position reports of amateur stations, being fixed or mobile, and formatted data (like weather reports).

Basically, the positions - normally determined by GPS - are exchanged by 'Packet Radio' over the air (VHF, UHF or HF), and decoded by appropriate software to be presented on a suitable map where all the stations are plotted. The transmissions are made on dedicated frequencies and relayed (digipeated) by participating stations in the APRS networks, this enables position reports on world-wide basis. Some satellites are as well able to act as digipeater (e.g. the International Space Station ISS)

Next to transmissions over radio, the information / positions are forwarded to a number of backbone servers on the Internet, so the data can be published world-wide.

The FIXED APRS station (ON7EQ)

This station - operating occasionally - is built around following components:
  • Transceiver  VHF 144.800 MHz
  • Software UI-View32

Some usefull links .....


Click here to download live screen capture !

The MOBILE APRS Station (ON7EQ-9 and ON7EQ-6 via satellite)

The station was once built around following components:
  • Transceiver ICOM IC-2725/ 50w VHF/UHF (one RTX reserved for APRS). THIS IS NOT RECOMMENDED ! Due to a bug in the 2725 firmware, it is possible to go in TX mode simultaneously on VHF digital mode (=APRS) and UHF voice ...  with disastrous results:  PIN diodes have been replaced at least 3 times in TX/RX switch section. The new IC-2820 is now used, and this rig is fully protected against these mishaps...
  • TinyTrack V3 APRS encoder
  • 'Mouse' GPS  or GARMIN GPS-III Pilot NMEA-183 out

At present  running Kenwood TM-D710 !



Some useful links .....

QR code for latest known positions ON7EQ-9

The APRS Satellite Gateway Station (ON7EQ-10)

This station receives APRS frames from (micro)satellites (or the ISS) and forwards these on RF and to the APRS Worldwide Web Network.

For practical reasons, the receiver is located about 30kms away from home QTH.. 

The station is built around following components:

  • Portable Radio
  • Bandfilter
  • TNC
  • Homebrew antenna system

Click to zoom on ISS APRS Satgate station !


The Portable APRS Station (ON7EQ-12)

I wanted to assemble an ultra-compact (75 x 55 x 15mm)  portable tracker, which can be connected to 'any' portable radio (Kenwood, Yaesu, Icom, ...). The result is the NANOTRACKER, a 'all-in-one' GPS + APRS encoder, which is self powered, and can be used for portable and/or mobile APRS reporting.

More details on the NANOTRACKER page.