Amateur radio direction finding, transmitter hunting, by triangulating a radio signals direction and plotting its bearing on a map. Hunters use Dopplers for tracking hidden transmitters anywhere in the San Francisco Bay Area.
http://www.thunt.org/
A collection of useful and interesting projects for the RDF enthusiast by Joe Leggio, WB2HOL
http://home.att.net/~jleggio/projects/rdf/rdf.htm
Describes a homebuilt mobile Doppler D/F unit, with theory, schematics, parts list, and all PC artwork.
http://www.silcom.com/~pelican2
Former supplier of the SuperDF. Tutorials and projects.
http://members.aol.com/BmgEngInc/
Fox hunting announcements, equipment, projects and links. Polar II setup information. Icom 706 mkII external S-meter installation. Pictures and antenna designs.
http://home.cinci.rr.com/w8eh/fox.html
On foot radio-orienteering, rules, projects, and event reports.
http://www.qsl.net/kq6xa/roca/