What is Fox Hunting?
Actually ARDF (Amateur Radio Direction Finding) is a more "technically correct" term for what we also call fox-hunting, hidden transmitter hunting, t-hunting, rabbit hunting and I'm sure that list could go on depending on whatever part of the country you are in. Fox hunting can be broken down into three general catagories with many local variations.
The most basic would be the typical on foot fox hunt in a small to medium sized park ususally consisting of a single transmitter. The fox is usually an automaticaly controlled transmitter sending out a variety of possible signals. The hunters (hounds) goal is to locate the tranmitter using any combination of direction finding skills.
Mobile hunts sends the "fox into the woods" in a vehicle while the "hounds" look for it in their vehicles. Classic US single transmitter mobile foxhunting is a map and compass exercise as well as a test of RDF skills. Successful hunters, (usually a team of two), pay careful attention to their own location and the bearing to the fox at all times, plotting them on street maps provided by the hound. They know that if they miss a fox bearing, they must wait a few minutes to hear the fox again. They also must obey traffic laws, since exceeding the speed limit or other violations means potential fines, money, that could be used on radios. In addition the hounds must keep an eye on time and distance. Many fox hunts are timed and start/finish mileage logged, excessive time and mileage can be used as a "penalty" against your final score.
Taking it to the next level is ARDF. This is a multi-transmitter hunt usually in a large park of several thousand acres and is completlely on foot. ARDF/Radio"O" is a combination of land navigation, map and compass reading as well as a test of RDF skills. Unlike in traditional orienteering where you search for a control point based upon a general location marked on a map, Radio"O" causes you to use your direction finding skills in addition to land navigation skills. Unlike in classic fox hunting where a single mobile transmitter is used, in Radio"O" you may be searching for as many as 5 transmitters, on foot, in a park or forest setting. Successful hunters pay careful attention to their own location and the bearings to all foxes at all times, plotting them on detailed orienteering maps provided by the organizers. They know that if they miss a fox bearing, they must wait four minutes to hear that fox again. They also must monitor the time, since exceeding the time limit (typically two hours) means disqualification. In other words, it is better to return under the limit with only one fox found than to find all five but take one minute over the limit. Each target transmitter has a distinctive identification, sent continuously in CW or MCW. Even without knowing Morse Code, it is still very easy to identify the individual foxes.
Since this is all done on the Amateur (ham) radio bands is a license required? No ... a license is not required, since you are receiving and not transmitting when you participate in any hidden transmitter event. Numerous ham radio clubs have frequent fox-hunting meets that you can participate in. However, having a license will add to your enjoyment and understanding of the radio direction finding aspects of the sport. The FCC provides an entry level license that includes a written test over basic radio principles, operating practices, rules & regulations. This "Technician class" license, which covers the 2 meter band, does not have a Morse Code requirement.
Please explore the following links for much more detailed infomration on equipment and techniques.
Amateur (Ham) Radio Links
Technical stuff
- Homing in - By Joe Moell, K0OV
- RDF projects - By Joe Leggio, WB2HOL
- Montreal Fox Controller - By Jacques Brodeur, VE2EMM
- Doppler products
- VK3YNG Foxhunting equipment
Other clubs / organizations / individuals
- IARU Region II ARDF
- Hidden Transmitter Hunting - By Byon Garrabrant, N6BG
- Radio Direction Finding Web Site - By Kevin Kelly, N6QAB