Spring 2006 Issue

Homing In

RDF for the Masses
Pulsed Emitters Near 220 MHz

 By Joe Moell, KØOV



This LoCATor pet tag weighs one-half ounce and has a breakaway link to prevent accidental choking of the animal. (All photos by Joe Moell, KØOV)


Visiting a high school last weekend reminded me how important the Internet has become in a relatively short time. On every bulletin board were flyers with URLs where students could find information, resources, and fun. Most of them probably can’t remember a time when there was no Internet.

This month marks ten years since I put my “Homing In” website online.1 I hoped that a site with basic information on hidden transmitter hunting would encourage more hams to try it. It would also answer the basic questions about radio direction finding (RDF) that I often received in letters and e-mails.

What I didn’t expect was the number of non-hams who stumble onto the site and want to learn about RDF devices that they can use. From stolen cars to model rockets and missing children, there’s a lot that people want to find and keep track of. From the beginning, I have tried to respond to every inquiry, no matter how vague or outlandish. In the process, I have learned a lot myself.
One of the first inquiries came from Tracy in Kansas, who wrote: “I have a friend who needs help with tracking his coonhounds. He says when they get out of hearing distance, it sometimes takes all night to find them. Yeah, I used to laugh too, until I heard how much money, prizes, and stud fees a good coonhound can bring in.” I suspected that my leg was being pulled when I saw this postscript: “Dorothy and Toto send their love.” Nevertheless, I answered as best as I could at the time.

As it turns out, Tracy was completely serious, and I discovered that a multi-million dollar market for RDF equipment has emerged among owners of hounds for sport hunting. When their dogs are following the scent of an animal such as a fox or raccoon, they may run several miles away from their owners. Radio tracking allows the humans to catch up and to round up any hounds that stray from the pack.

PL Boards and RDF Gear

Near the top of the list of companies riding this wave of demand for consumer RDF hardware is Communications Specialists of Orange, California.2 This is the same ComSpec that has made subaudible tone (CTCSS) encoders and decoders for well over 20 years. However, according to owner Spence Porter, WA6TPR, “Our main business has not been building PL stuff. It’s been building homing stuff.”

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