[TowerTalk] Symptoms of antenna interaction?

[Randy Lake]

I have a 2M18xxx and a 6M9KHW and M2 told me that 7' was the
minimum separation to avoid interaction. Interaction MAY affect SWR but
more likely will create a distortion of pattern. My 2M is on top of the 6M
now by 8ft. I would spin the 6m antenna 90 degrees to the others and see if
you notice a difference.
Randy N1KWF

On Tue, Mar 23, 2021 at 3:30 PM Al Kozakiewicz <akozak at hourglass.com> wrote:

> Still have a foot of snow on the ground, so I'm not quite ready to climb
> yet.
>
> See photos on QRZ page.
>
> I have 3 antennas on a 10' mast sticking a total of 8' out the top of the
> tower. From top to bottom, 2M7, 6M3 and a C3, all equally spaced.  All were
> tuned to resonance on the ground.
>
> Now up in the air, the C3 and 2M7 are fine, but the 6M3 is useless. The
> SWR is about 3:1 and Z=~70 ohms at the minimum for both.
>
> Is this symptomatic of interaction, i.e. feed point characteristics change
> while resonance frequency remains the same? If so, what is a recommended
> solution? The one possibility I haven't checked yet as it requires climbing
> is a bad rotor loop cable.
>
> Al
> AB2ZY
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-- 
Randy Lake N1KWF
73 Gunn Rd.
Keene,NH