Eliot in June 2020

Eliot Mayer

Engineer, Radio Amateur, Musician, UU


W1MJ Fox


My participation in hidden transmitter hunts - AKA fox hunts - led to an interest in designing and building fox transmitters. In 2023, I updated my original fox design to extend deployment time and to monitor the battery. The update provided experience in PC board design, the Raspberry Pi Pico, and Python programming.

The W1MJ Second-Generation Fox

Automated Transmitter for Hidden Transmitter Hunts

W1MJ Fox2

The W1MJ FOX2 is an automated transmitter designed for use in hidden transmitter hunts. The fox plays pre-recorded audio messages at regular intervals using a low-cost VHF/UHF FM transceiver. It has two power-conserving modes to extend deployment - Scheduled & On Demand. A Raspberry Pi Pico serves as the controller and MP3 player.

The Original W1MJ Fox

The orginal fox used a simple MP3 player interfaced to a walkie-talkie, playing a set messages over and over, all day and all night.

Design and Assembly Article: PDF | Word