Resonant Feedline Dipoles


Carol Todd:
We are going on a dxpedition to the Marshall Islands and Micronesia. We are thinking of making up some Resonant Feedline Dipoles for our favorite frequencies and using them as verticals near the shoreline on the atolls we will be visiting. Our question is: Could we make these directional through the use of a reflector  (as Force 12 does with their verticals) and would it be possible to make the reflector so that it also could also be a director by installing some type of stub that could be put in or out of the circuit to change its effective length? This would allow us to reverse the radiating direction without moving the antenna. Any help on this will be appreciated - the more detailed the better. We will be sailing in the next couple of weeks so we must get our stuff together. Thanks, Jim & Carol on the sailing vessel "Morning Wings".   See our website at:

Denny Hilbert:
Confused me, you mean resonate dipoles with a coax feedline. I would use a telescopic mast and adjust it to either mode and then space it .12wL to .2 wL from the vertical dipole itself. The bottom of the director/reflector
will need to be insulated from ground since it's a 1/2 wL and would be a voltage point. 495/freq for reflector and 458/freq for element lengths should get you in the ball park. 4 or 5db fowward gain and 10 or 12 db front to back should make a differance in signal. You could make a list of freq/spacing/ref-dir lengths and be able to set up quickly.


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