Links for RDF, T-hunting, and Radio-Orienteering

Vehicular T-Hunting

Find out how to get involved in mobile T-hunts in your area of the USA by visiting these local T-hunt Web sites. (Listings are alphabetical by state and city.)

Some localities have regular (or occasional) mobile T-hunts, but no Web coverage of them. Find out about hunts in the areas below by sending e-mail to the local Homing In Correspondent (Listings are alphabetical by state and city. E-mail addresses have been obscured to foil spammers. Replace "-at-" with "@" when addressing your e-mail.):

Non-commercial Web sites regarding technical RDF topics have been posted by these individuals and groups (alphabetical by last name):

Mobile T-hunting is not limited to the USA. Here are some other places around the world where it is done:

On-Foot Foxhunting

On-foot foxhunting (also called foxtailing, radio-orienteering and ARDF) is growing rapidly in the USA. In addition to southern California ARDF events and upcoming championship news at this site, you can see these other sites for information on stateside ARDF activities:

Here are e-mail contacts for radio-orienteering leaders in other parts of the USA and Canada (Listings are alphabetical by state/province/city. E-mail addresses have been obscured to foil spammers. Replace "-at-" with "@" when addressing your e-mail.):

ARDF is the predominant style of RDF contesting outside the USA. There are Web sites about it in many countries (in English unless otherwise indicated).

Equipment Suppliers

Here are the past and present sellers of equipment and software for RDF and related purposes to the Amateur Radio market, in alphabetical order. A listing here does not imply an endorsement of products.

Also see my Hardware Sources page for links to suppliers of circuit boards, special parts, and complete kits for RDF-related home construction projects.

Sophisticated RDF equipment and radiolocation systems and services are advertised by the following companies to the government and military markets, as well as to law enforcement and industry. As before, a listing does not imply my endorsement, or even the availability of actual products.

Specialized transmitters and RDF tracking equipment for wildlife management (and sometimes for pet and human tracking) are advertised by these companies. Same disclaimer applies. For more on research uses of RDF, see Homing In for July 1995, January 2003, and Summer 2005. Also see the T-Hunt book.

RDF is an important tool for search and rescue. Here are some sites with information about it:

To list your site or become a Homing In Correspondent for your area, send e-mail to

Surfing suggestion: Is it necessary to build or buy a doppler set to be competitive on hidden transmitter hunts? Find out what southern California winners use in the Let's Go T-Hunting page.

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This page updated 13 November 2023