District 1 OHIO ARES

...When all else fails!

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Tape Measure Beam Optimized for Radio Direction Finding:

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This antenna evolved during my search for a beam with a really great front-to-back ratio to use in hidden transmitter hunts. This design exhibits a very clean pattern and is perfect for RDF use. It trades a bit of forward gain in exchange for a very deep notch in the pattern toward the rear. (You could optimize the design for more forward gain, but at the expense of a really good notch in the pattern toward the rear.) It is a design that can be constructed using only simple hand tools (no machine shop needed) and still perform well. It has been duplicated several dozen times by other local hams and has been successfully used as a club construction project. When I designed this antenna I had one basic idea in mind. It had to be easy to get in and out of the car when hunting for a hidden transmitter. This would be accomplished by the use of steel "tape measure" elements. These elements could fold easily when fitting the antenna into my car and yet still be self supporting. I decided to use three elements to keep the boom from getting too long.
 

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Toledo, Ohio
Last Update: 4:51pm Sep 10, 2010
Partly Sunny Today: Partly Sunny
72°F | 54°F
Rain Showers Likely, Probability Of Precipitation: 70% Tomorrow: Rain Showers Likely
73°F | 56°F
PoP 70%
Partly Sunny Sunday: Partly Sunny
74°F | 53°F
Current Conditions at Toledo Express Airport, OH:
A Few Clouds
A few clouds
69.0°F
wind is from the east at 10.4 gusting to 16.1 mph (9 gusting to 14 kt)
barometric pressure is 1016.7 mb
visibility is 10 miles
(Last Updated on Sep 10 2010, 4:52 pm EDT)