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The Roanoke Doppler Page
On January 13th, 1998 the topic of the Nittany Amateur Radio Club monthly meeting was the building of the Roanoke Doppler direction finder. This web page provides some background and some photos of the event.What is the Roanoke Doppler?
The Doppler direction finding effect was first discovered by Austrian physicist Christian Doppler in the nineteenth century. When the distance between a transmitted signal and a receiver is changing, the received frequency of the transmitter is shifted - lower if the two are moving apart, and higher if the two are moving closer. A Doppler effect direction finder was first described by Terrance Rogers, WA4BVY, in a 1978 QST article. In the late 1970's Chuck Tavaris, N4FQ, designed a simple and inexpensive Doppler direction finder as described in Chapter 9 of "Transmitter Hunting" by Joseph d. Moell, K0OV, and Thomas Curlee, WB6UZZ. Since Chuck lived in Roanoke, Virginia at the time it came to be know as the Roanoke Doppler. Rod Kreuter, WA3ENK, worked with Chuck at the time and modified the design to the kit built by the NARC.How Roanoke Doppler building night got started
In 1996 Rod, WA3ENK and his XYL Joyce, KA3SWK, decided to participate in the NARC fox hunt, pretty much at the last moment. Rod built a two element cubical quad and they came in dead last - never finding the fox. Luckily, in the 1970's Rod worked with Chuck Tavaris. Chuck designed what he called "the secret weapon" and Rod helped him with testing and development. It was a long time before Chuck would reveal his design to the other hunters, but it was hard to hide the eight 1/4 wave whips on top of his Ford Bronco and harder still to understand why Chuck always won. The design evolved and the eight antennas became four and the electronics got better. When he finally shared his ideas with the rest of the hunters it became known as the Roanoke Doppler. The week after losing last year Rod began to build a Roanoke Doppler of his own. It worked pretty well, finding the fox in good time. The NARC requested that Rod be the speaker at a club meeting on the topic of the Roanoke Doppler and it's FUNCTIONING. It was then decided to go ahead and build the unit as a club, for many diverse reasons, amoung them being interest in doing some type of building as a club, infrequent problems with a jammer on a local repeater and the possibility of more intriguing fox hunts.Photo Gallery of Roanoke Doppler Building Night
Our fearless president looks
up from his task
Big smiles - it must be fun to build 
Another builder getting
started
A father and son team working closely together 
Doing some heavy observing
Our vice president gets down to work 
What a lineup