I have a KT-36XA 9 feet above a 40-2CD. I have noticed a serious interaction
between the two - specifically, the SWR on 40 goes above 3:1 when the XA boom
is parallel to the elements of the 40 - i.e. the booms are 90 degrees to each
other. I have not noticed any problems on 10-20 on the XA. I used to have the
same setup with the KT-34XA and don't recall having the problem, so I suspect
it is caused by the fact that on the '36, the parasitic elements are grounded
to the boom by metal boom-element clamps, and this makes the boom resonant on
40. In my setup, the XA is on top, and the 40 is on a swinging-gate mount, so
they are independantly rotatable. If I really need to, I can rotate the XA to
fix the problem - but this would not be a good solution for multi-op. I think
if you mount them on the same mast, with the booms parallel, there should not
be a problem. Anybody have a ferrite bead choke with an ID of 3 inches?
-Tony, K1KP
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