[TowerTalk] XM-240 and KT-36XA Interaction

[Andre Van Wyk]

I had a KT34XA and a 40M2 on the same tower. The 40M2 was on the top.

I had serious interaction, and the SWR on the 40m beam went crazy...

I then mounted the 40m beam 90 deg to the KT34XA and this fixed the problem.

Only issue was keeping sanity with rembering which beam pointed where.....


73
KR5DX



----- Original Message -----
From: "Tony Brock-Fisher" <barockteer at aol.com>
To: <towertalk at contesting.com>
Sent: Saturday, January 05, 2008 8:31 PM
Subject: Re: [TowerTalk] XM-240 and KT-36XA Interaction


> 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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