80 Meter ARDF Fox, PIC Based

The Micro Fox 80 is a low cost 80 meter ARDF transmitter developed by Jerry Boyd, WB8WFK. The transmitter is based on a PIC 12F629 microprocessor controlled by a modified version of the Montreal Fox Controller software and other low cost parts.

Features of the fox include:

  • Control program revised and written in PIC C
  • Has Sync connector
  • Supports Morse code formats used at the 2006 and 2004 ARDF world championships
    • Warning tone for end of cycle ( 2004 and 2006 WC)
    • Slow CW for first half of cycle (2006 WC)
  • Simple RF amp and antenna matching network for 22 foot wire antenna
  • Depending on surrounding conditions a range of almost 2 miles was achieved
  • A full length ARDF course was set at the old east mountain ARDF site; 2N2222A PA used  
    • KC5VVB had no problem using his Altai-3,5 European receiver
    • All transmitters had usable signal at start point
    • This site is much flatter then the Doc Long Site
    • Has been used at 3 ARDF events at Doc Long in conjunction with New Mexico Orienteers meets ( Course distance shortened to accommodate rugged terrain to allow all transmitters to be copied at start point)
    • Original units used 2N2222A. New version will use BFS17LT1 NPN RF transistor. Hope to get more RF output
  • Added filter on Sync input to prevent ESD events from re-setting the microcontroller
  • Runs all day on a 9 volt battery
  • Current set of 5 transmitters are built on point to point wired boards. Have draft PCB layout for additional builds

Bottom line Easy to set up and good for ARDF practice. In quantity the transmitters could be produced for less than $10.00


A picture of the transmitter and schematic follow.  A presentation made to NM-ARTS can be found in the presentations archive.

Click on the images for full size versions. 

For more information contact Jerry Boyd, WB8WFK.