80m Practice Fox

Another great build project of Les Tocko VA7OM, constructed by 10 members on 20 September 2026 ... this one is an 80m transmitter or "Fox" for practicing foxhunting skills.  Each has been programmed to transmit in CW the letter "M" (2 dashes) followed by the letter "O" (3 dashes) followed by the builder's callsign.   

Starting with a conventional circuit, Les modified the antenna matching network, updated the firmware code to allow adding a call sign ID, and designed a custom PCB using through-hole parts so it would be easier for club members not experienced with small surface-mount components.

When switched on, it continuously sends "MOE" in Morse code for easy tracking, interspersed with the owner or operator's call sign to stay fully compliant with station identification requirements.

Powered by 2 AA batteries, the MicroFox is a compact 80-meter transmitter built around just two main integrated circuits.  The circuit is comprised of three functional units: the Microcontroller, the Crystal Oscillator, and the Output Power Amplifier.

The microcontroller is the brains of the device, acting as the keyer and controller. It handles all the timing and continuously generates the CW code for the "MOE" identification loop and operator call sign output. 

The crystal oscillator generates a stable carrier signal at 3.570 MHz to key the RF signal on and off according to the programmed Morse code.

The power amplifier amplifies the RF carrier signal, keys the output, and feeds the RF signal to the short 7.5 ft wire antenna and 7.5 ft counterpoise on 80 meters

For those who wish to replicate the Microfox, a more detailed description will be found in the next SARC Communicator to be issued around 1 November 2026.