Topband: Detuning towers and K9AY loops

[Tom Rauch]

> ON4UN's book shows using a MFJ-931 "ground tuner" to do the above ...
> 
> Anyone used that unit? Results?  (ah ... yet another project ...)


Any tuner that will hit the correct reactance will do that Billy, as 
well as any length of coax that you cut to the correct length.

When I use my four-square, I detune the tower by open circuiting a 50 
foot length of coax used to feed the L network that matches the 
tower. The length was selected to minimize tower re-radiation when 
using the four square.

When I use my center tower, I detune the surrounding four square by 
shorting the coaxial feeders to each element. That opens the base of 
the 1/4 wl antennas, just like Peter WW2Y posted.

When I receive back through that array, I do both at once!

73, Tom W8JI
W8JI@contesting.com