I have MAG240N (90') mounted above a C31XR (82') so some of the same things
will apply to your setup. The MAG240N is a very nice antenna. It covers the
entire band with decent F/B (the 402-CD did not have decent F/B across the
entire band). The main reason I bought the MAG240N was to replace my 402-CD
because it doesn't have any resonances in the other bands. This means you
can put it closer to other antennas without interaction. I believe Force12
says you can put this antenna 6-7' next to a 15M antenna without causing
problems. I separated mine 8'.
I had put up the C31 first and checked resonance. Then I put up the MAG240N
by itself to check resonance. Then I put up both together and there were no
changes. By the way the booms are in parallel. I seem to still be
competitive on 15M. Don't have a direct way to compare 15M to another beam
to make sure no interaction. My other tribander is down the tower at 42' so
no way to use that as a real reference.
As an example of interaction, at WP2Z we had an A3 on one tower and a C3E on
another tower, both at about the same height. They performed in a similar
fashion with the edge given to the C3E. We moved the A3 above the 402CD so
we could rotate it from the shack as compared to our rope method of rotating
it. We could only put it up about 3' above the 40M beam. 10M and 20M still
seemed to be almost as good as the C3E. But 15M now is consistently 2-4
s-units down from the C3E. SWR didn't change much on 15M but performance
I followed the instructions in the book by hoisting up each element first to
tune each one. I pulled them up 30' in a tree. Didn't see much change when I
assembled the antenna and have it at its final height. Mine is set up for
7.80. It's less than 2:1 across the entire band.
If I was starting from scratch I would buy the combination you bought except
I would see if I could add 2 element 30M to the MAG240N. I have a WARC7 at
104'. Your combination would eliminate the need for the WARC7.
[mailto:firstname.lastname@example.org] On Behalf Of Jim Walker
Sent: Thursday, January 05, 2006 10:56 PM
Subject: [TowerTalk] Yagi Separation on a Mast
Hello Fellow TowerTalkians,
I plan to locate my 20 meter Steppir, 4-element yagi and Force 12 Magnum
240N, 2-element, 40 meter yagi on the same mast.
I would like to ask those with similar setups, what your experience is with
respect to how much separation is needed between the two antennas.
I am told I should be able to orient both antenna's booms in parallel
without interference. Again, what is your experience?
Thanks for everyone's responses.
Jim - KB0X
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