[TowerTalk] CC XM240 above a big Tribander

[W0MU Mike Fatchett]

When I was in Montana, I had an ungrounded XM240 and every time a storm
would brew up you could hear the sprarking between the element and the
boom in person and obviously on the radio.  At night you could see it.

I put a ground strap on my XM240 here in Colorado and I don't have that
problem.  The XM240 should have minimal interaction.  Mine is 10 - 12
feet above my SteppIR.

Mike W0MU

On 4/17/2014 6:26 AM, N2TK, Tony wrote:
> Wasn't there something said years ago about grounding the reflector on the
> XM240 so it would work like the earlier 402CD? I can't remember if this was
> intended to reduce the interaction on 15M or if you had the antenna at right
> angles to a 20M beam the grounding would reduce a 20M resonance on the
> XM240?
> Lots of cobwebs in the belfry on this one.
>
> 73,
> N2TK, Tony
>
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of Bill
> Parry
> Sent: Wednesday, April 16, 2014 11:40 PM
> To: 'Dave Hachadorian'; 'reflector Towertalk'
> Subject: Re: [TowerTalk] CC XM240 above a big Tribander
>
> Dave
>
> I guess that it is all a matter of antennas and situations. I put up a XM240
> at about 133 feet above a Force 12 C3E at 120 feet or about 13 feet apart.
> The interaction between the two was fairly obvious and the SWR on 15 was not
> good.  I turned the C3E 90 degrees and the problem vanished. I had the
> antennas down after a lightning strike about 4 years ago and tried it again
> with the same results.
>
> Both antennas work just fine in the current configuration.  I was sure that
> the 13 feet would be enough but it definitely was not.
>
> Bill W5VX
>
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of Dave
> Hachadorian
> Sent: Wednesday, April 16, 2014 8:50 PM
> To: reflector Towertalk
> Subject: Re: [TowerTalk] CC XM240 above a big Tribander
>
> My XM240 is six feet above a KT-34XA.  The booms are aligned.  It works for
> me.
>
> After you get the antennas installed, run a f/b ratio test on the tribander.
> Front-to-back ratio is easy to measure, and is the most sensitive test for
> adverse interaction.  Here is more info:
> http://lists.contesting.com/archives//html/Towertalk/2006-08/msg00634.html
>
> I just noticed an error in the last paragraph of that 2006 posting.  The
> last paragraph should read, "Sometimes just changing the length of the
> 40-2CD's feedline, or shorting/opening its feedline when the antenna is not
> being used will solve interaction problems."
>
> Dave Hachadorian, K6LL
> Yuma, AZ
>
> -----Original Message-----
> From: Marsh Stewart
> Sent: Wednesday, April 16, 2014 5:15 PM
> To: towertalk at contesting.com
> Subject: [TowerTalk] CC XM240 above a big Tribander
>
> How close vertically on the same mast can a new CC XM240 be to a big
> 10/15/20M tribander without serious interaction?
>
> Marsh, KA5M
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