Radio Direction Finding, a.k.a. “Fox Hunting”

https://commons.wikimedia.org/wiki/User:Malene

(spoiler- no foxes or other animals are hunted whatsoever)

Have you ever played hide-and-seek? Sure you have! It was a lot of fun (still is). Now, imagine doing it on a massive scale- the entire county is your playground. This is in essence, the fun behind “Radio Direction Finding” (RDF), otherwise known among ham radio operators as a “fox hunt”. . A “fox hunt” is where one ham hides a transmitter (“the fox”) somewhere within a known set of boundaries (such as inside the county border lines) and other folks then try to find him/her. The quickest person/team to find “the fox” is the winner! It’s similar to geocaching, but you don’t have the coordinates of the “fox”.

The activity has very old roots in radio operations, and most famously done by the military during “Huff Duff” (HF) direction finding operations to zero in on German U-boats that threatened British and American fleets in the Atlantic Ocean in the Second World War.

Shipboard RDF equipment on HMS Belfast by Rémi Kaupp [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons
We hams use it for more peaceful purposes, such as:

  • Finding sources of harmful radio interference
  • Locating lost people
  • Finding downed airplanes or other vehicles
  • Pure, clean fun- the thrill of the chase!

Here’s what a ham radio “fox hunt” transmitter can look like:

“Fox Hunt” Transmitter

To participate, you only need a few tools:

  • A directional antenna
  • A magnetic compass (or a smart phone)
  • A map, straight edge, and pen (or a smart phone)
  • A ham radio capable receiver

Here’s an example of a team using a directional antenna:

NG2M, J.D. (left) and AJ4JZ, Bill (right), take a reading using a “Moxon” antenna.

Our club builds cheap & effective directional antennas as projects regularly:

2017 July Moxon Build Meeting

GCARS Feb 2016 Activities!

Now, there are even smart phone apps to help you find the “fox” even more quickly:

Does this sound fun? (It should!) Join us on the next “fox hunt”- you don’t even need a license to participate (but you will have more fun if you do!)

Hams who’ve found the fox: (left to right) Robert, K4VAV, Annlette, KV4WB, Pat, N4DOX, and Pat, K1CY