BL> with a circle of 10 (or so) red LEDs on the top and a couple 
 BL> mini-toggles on the rear edge (for power, attenuation, etc...). This 
 BL> unit was in turn connected via a cable to another smaller box with 
 BL> what looked like large nails (same number as on the other box) 
 BL> pointed up through the top of it
  Bruce-
     A similar system was sold by a company called Doppler Systems, Inc.  
I remember their advertisements from years ago, and believe they are still 
around.
     As I understand the principle of its operation, the vertical rod 
antennas are switched-on in diametrically opposite pairs, in a sequence 
around the circle.  This is the electronic equivalent of rotating a single 
pair, and a similar doppler effect is realized by measuring the relative 
phase of received signals from the two antennas.  I've seen photographs of 
such a system with as few as 4 vertical rods.
     73, Fred, K4DII
 This copy of Freddie 1.2.5 is being evaluated.
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