Fox Hunting or T-Hunting (hidden transmitter hunting) or Radio Direction Finding.
Locating a radio transmitter, whether hidden, intermittent, interference-generating or just for fun can be a challenging sport. It tests your knowledge of radio theory, navigational skills, equipment operational skills and just plain detective skills.
Here are just a few internet resources available:
Let’s Go T-Hunting : http://members.aol.com/homingin/SCalStyle.html
All about Radio Direction Finding : http://members.aol.com/homingin/
Piedmont Transmitter Tracking : http://www.qsl.net/nz0i/index.htm
Transmitter Hunting : http://www.qsl.net/n6bg/thunt/
Fox hunting can be as simple as walking around with a handheld HT to an elaborate suite of commercially-made radio direction finding equipment. It can cost no money at all to thousands of dollars. Many hams choose to build simple, low cost antennas and attenuators rather than buy them. Here are some web sites that may be of interest.
RDF yagi / tape measure : http://home.att.net/~jleggio/projects/rdf/tape_bm.htm
A TDOA Antenna Unit for Fox-Hunting : http://webhome.idirect.com/~griffith/tdoa.htm
RDF projects to build : http://home.att.net/~jleggio/projects/rdf/rdf.htm
PTT: VHF On-foot Hunt Equipment : http://www.qsl.net/nz0i/equipment/vhffoot.htm
WB2HOL Tape Measure Beam Product Reviews : http://www.eham.net/reviews/detail/1443
RDF2 two element, close spaced Yagi antenna by dxzone.com: http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=9652
The bible of fox hunting is undoubtedly this one:
Transmitter Hunting: Radio Direction Finding Simplified (Paperback) by Joseph D. Moell, Thomas N. Curlee
Here’s a report and map (foxhunt0105.html) from an EARC fox hunt of May 2001 in Honolulu