Tracker3 Series APRS Tracker

(Available through our online store)

For manuals and downloads, see the support section below.

The Tracker3 is the successor to our popular Tracker2 series. It features a much more powerful 32-bit processor with improved DSP capabilities, better telemetry support, USB, and more room for expansion.

  • Plots received positions as waypoints - APRS stations, objects, and items received over the air can be passed to a GPS receiver to be plotted on its map display. When used with a supported Garmin or Magellan GPS receiver, waypoints will be created with appropriate map symbols, comment text, and elevations.
  • KISS support - Use with any packet program that supports the standard KISS interface protocol.
  • APRS Digipeater - Supports multiple aliases, WIDEn-n and TRACEn-n style callsign substitution with dupe checking, hop count limiting, and optional preemption. May be used simultaneously with tracking and KISS functions.
  • Command console - A traditional TNC2-style serial console provides a simple, platform-independent configuration interface. Additionally, APRS station-to-station messages may be sent and received from the command line.
  • Remote control via APRS - Most of the commands available at the console may also be issued through APRS station-to-station text messages. This allows the unit to be reconfigured from anywhere in the world with APRS access. Access can be limited by callsign and through the use of a secure one-time-password scheme.
  • Upgradeable - Firmware updates are free and easy to install. Firmware images can be downloaded directly from the website with the Windows-based configuration utility, or they can be transferred to the unit from any XMODEM-capable terminal program for cross-platform compatibility.
  • Flexible and Expandable - Extra analog inputs and digital I/O lines, plus a Dallas 1-wire bus, allow connection of a wide variety of devices.
  • SmartBeaconing™ - APRS tracking with SmartBeaconing™ support for automatic beacon rate control, compressed format support for shorter packets and better precision, and timeslotting for efficient, coordinated channel usage.
  • Weather Station Support - Supports Peet Bros, AAG 1-wire, and LaCrosse WS-2300 series weather stations.
  • On-board temperature and voltage telemetry (OT2m only)
  • Scripting - A simple scripting and macro language allows a degree of flexibility and programmability not found in other trackers.
  • Dual serial ports (via splitter cable for OT3m, or front-panel data jack for T3-135).

Tracker3 model OT3m

The standalone OT3m model has all of the above features, and comes fully assembled in a heavy-duty steel enclosure. The OT3m also includes a 7 amp solid-state relay for remote or timed control of DC loads or automatic control of radio power.

Tracker3 model T3-301

The T3-301 is a combination of the Friendcom FC-301/D VHF data radio and a Tracker3 daughter board. All of the Tracker3's standard functions are present in the T3-301. In addition, the transmit and receive frequency and RF power output (1 to 5 watts) can be set through the Tracker3, including by remote command.

The radio has FCC Part 90 and CE certifications, making it legal for use on commercial frequencies (from 136 to 174 MHz) in both the US and Europe.

Tracker3 model T3-135

The T3-135 version is an add-on board designed to fit the Alinco DR-135T (as well as the -235 and -435) in place of the original EJ-41U TNC. Like the regular Tracker3, it acts as a bidirectional tracker (transmitting positions and plotting received stations as waypoints), digipeater, and limited KISS TNC. However, it lacks the on-board voltage sensor of the standard board.

Tracker3 model T3-Mini

The T3-Mini is a miniature version of the Tracker3 measuring 1.73"x1.12"x0.215" (44x29x5.5mm) and weighing 5.5 grams. It has all of the software features of the other Tracker3 models, and provides 4 analog inputs and 13 general-purpose digital I/O pins. Its serial ports can be configured for RS-232 or TTL operation.


  OT3m T3-135
Voltage DC 6.5 to 28V 5 volts (powered by radio)
Current 40 mA idle, 50 mA transmitting
350 mA @ 5 V available for GPS
40 mA idle, 50 mA transmitting
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) internal
Serial Connector DB9 male (dual RS-232) Rear DB female, front 3.5mm jack
Dimensions 4.2" by 3.2" by 1" 2.3" by 1.4" by 0.3"
GPS Interface NMEA in/out, Garmin Binary NMEA in/out, Garmin Binary


Tracker3 Support

Configuration Program

The otwincfg.exe configuration program can be used with all of our trackers. For otwincfg connection problems, see the FAQ.


The Tracker3 Wiki contains detailed and up-to-date information on the Tracker3.


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. Right-click to save the file.

t3-56398.s19 Tracker3 firmware April 16, 2013

Manual and Schematics


The .inf file below must be installed for Windows systems to recognize Tracker3 devices when using a USB connection. Most other operating systems will not require any special configuration.

Tracker3 Discussion Forum

The Tracker2, Tracker3, and OpenTracker USB series are covered by the Tracker2 Yahoo Group


Purchase the Tracker3