OpenTracker+ (OT1+)

Please note that the OT1+ is currently being phased out due to component obsolescence. The OpenTracker USB has replaced it as our entry-level APRS tracker.

The OpenTracker+ is an APRS tracker that can also receive data from other stations and has waypoint output capability. Use the OT1+ to report position, course and speed, time, and altitude when connected to a GPS -- not just from a vehicle, but anything, including a bicycle, weather balloon, or backpack. Or, use the OT1+ to encode and transmit data from a supported weather station. The tracker will also report telemetry from its onboard temperature and voltage sensors, and an external counter input can report a cumulative total of counter events or the number of events since last transmission. The OpenTracker+ replaces the OT1x and OT1m series. The OT1+ added waypoint output capability, increased program space and RAM, and a simplified hardware design. Available as a kit or fully assembled.

The OpenTracker+ SMT is a surface-mount version of the OT1+, with a 24-pin DIP form factor. This board has the same features as the OT1+, except it does not include a built-in temperature sensor or LEDs. Only available assembled.

Major features include:

  • APRS telemetry output
  • Fixed location operation for telemetry with no GPS
  • NMEA waypoint output
  • Dual configuration profiles with flexible selection
  • On-board temperature and voltage sensors
  • Supports 1-wire and Peet Bros WX stations
  • Drive an external relay for radio power control
  • Supports 1200 and 300 baud AFSK operation
  • PSK31 support for PropNet^31 Operation
  • Base91 compressed positions with 1-foot resolution
  • SmartBeaconing™ for adaptive beacon rates
  • Digital event counter, cumulative or since last transmission
  • Free firmware upgrades directly from the website, no special hardware needed
  • Source code released under Modified BSD license


  OpenTracker+ OpenTracker+ SMT
Voltage DC 6.5 to 28V DC 6.5 to 28V unregulated or
5V DC regulated
Current 8 mA idle, 20 mA transmitting
Max 200 mA @ 5 V available for GPS
8 mA idle, 20 mA transmitting
Max 200 mA @ 5 V available for GPS
Modes 1200 bps AFSK (send and receive)
300 bps AFSK, PSK31 (send only)
1200 bps AFSK (send and receive)
300 bps AFSK, PSK31 (send only)
Radio Connector DB9 female (Kantronics pinout) pin header
Serial Connector DB9 male (RS-232 DTE configuration) pin header
Dimensions 2.5" x 1.6" x 0.75" 1.22" x 0.72" x 0.2"(excluding pins)
31mm x 18mm x 5mm
GPS Interface NMEA in/out NMEA in/out



OpenTracker+ Brochure (two page .pdf).

OpenTracker+ Support

Configuration Program

The otwincfg.exe configuration program can be used with all models of OpenTracker and Tracker2. For otwincfg connection problems, see the FAQ.


The easiest way to update the firmware is to use the 'Load Firmware from Web' option in the configuration program.

The following firmware files are provided for off-line use. This firmware is only for use with the OpenTracker+.

otplus.s19 OpenTracker+ standard firmware build 54908 March 18, 2009
otplus-1wirewx.s19 Dallas 1-wire weather station support December 17, 2008
otplus-peetbros.s19 Peet Bros weather station support December 17, 2008
otplus-kiss.s19 KISS firmware December 17, 2008
otplus-smt-telem.s19 Extended telemetry support for OT1+ SMT December 17, 2008
otplus-i2ctx.s19 OpenTracker+ firmware for RTrak April 12, 2008
otplus-psk31.s19 PSK31 (31.25 bps BPSK) support for OT1+ SMT August 6, 2007


Revision History, Manuals, and Schematics

OpenTracker Discussion Forum

OpenTracker Yahoo Group


Purchase the OpenTracker+