KENTUCKY PORTABLE CLUB • RADIO DIRECTION FINDING
Somebody hides a transmitter. Everybody else finds it with a radio, a directional antenna and a little detective work. Here's how to hunt, how to build a $20 beam, and a map that plots your bearings for you.
A "fox" is a small, low-power transmitter — usually on 2 meters FM — that sends a tone, a short message or CW and its callsign. Your local hunt sets the frequency; many U.S. hunts use 146.565 MHz simplex.
Teams drive, take bearings from high open spots, plot them on a map and close in. Usually the fox is hidden somewhere within a few miles. Lowest time or mileage wins.
One or more foxes hidden in a park or woods — perfect for a KPC campout. Hunters walk with an HT and a handheld beam. Great for families and new hams.
Amateur Radio Direction Finding — the international, orienteering-style version. Five foxes in the woods, one minute each, a map and a compass. There are U.S. and world championships.
Magnetic vs. true north: a compass (and your phone) points to magnetic north. Maps use true north. In Kentucky, magnetic north is a few degrees west of true — the bearing map corrects this for you.
Each bearing draws a line. Where the lines cross is where the fox is. Use your phone's compass and GPS in the field, or add bearings by hand.
Then tap the spot on the map where you took it — or use your GPS spot.
About −2° to −6° across Kentucky. Look yours up (NOAA) ↗
Bearings are saved on this phone until you clear them. Phone compasses get thrown off by cars and metal — step away from the vehicle.
The classic fox-hunting beam: three elements cut from a steel tape measure on a PVC boom. It folds flat, costs about $20, and has a deep null off the back. Dimensions below are the popular WB2HOL design for 2 m — change the frequency to scale it.
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Near the fox, the signal floods your radio from every direction and the beam stops helping. These cut it back down so you can keep homing in.
A tiny box between the beam and your HT. It mixes the fox signal with a 4 MHz oscillator, so you listen about 4 MHz away (146.565 fox → 150.565 or 142.565) and turn a knob to make the signal as weak as you need — even right next to the fox.
Your HT must receive outside the ham band. Homebrew kits are common club builds.
Every transmitter leaks a weak copy at 3× its frequency. A 146.565 fox also shows up faintly on 439.695 MHz. Tune your dual-band HT there when the main signal is pinning the meter.
Works only when you're quite close.
Take the antenna off (or turn the squelch off and use a rubber duck), hold the HT flat against your chest and turn slowly in a circle. The signal dips when your body is between the radio and the fox — the fox is behind you.
Also try: step attenuator, tuning slightly off frequency, and pointing the beam up and down.
Running a hunt at a campout or club meeting? A few things make it fair, fun and legal.
Amateur Radio Direction Finding blends fox hunting with orienteering. It's run under IARU rules worldwide.
| Bands | 2 m (FM/AM tones) and 80 m (CW) |
| Foxes | Five low-power foxes on one frequency, each on for one minute in turn |
| IDs | Each sends Morse "MO" plus its number: MOE, MOI, MOS, MOH, MO5 |
| Finish | A beacon at the finish sends all the time on its own frequency |
| Course | About 6–12 km in the woods on an orienteering map, 2–3 hour limit |
| Rules | On foot, no GPS. Categories by age and gender set how many foxes you need |
Shorter versions — sprint and foxoring (low-power foxes at marked points on the map) — are great starter events and easy to set up at a park.
Want a KPC fox hunt at the campout or a park day? Tell us →
NO LICENSE NEEDED TO HUNT — BRING THE KIDS
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