[VHFcontesting] Cushcraft A270-10S (triband VHF/UHF) beam question

[Alex]

Hi John,

I bought two A270-10S antennas with a phasing harness from a fellow ham. I
put the stack at 30 feet (horizontally of course) and did some experiments.
I found that the performance was very disappointing on both bands . A simple
4 stack of halos at the same height would outperform the stacked beams on
70cm. It was marginally better than a single stack of halos at the same
height on 2 meters. The feed line lengths were the same on all antennas,
except that the halos were fed with RG-8x and the beam was fed by the
Wireman's LMR-400 equivalent...

Then I decided to try a single beam and had someone a few miles down the
road send a test signal while I rotated the antenna to get an idea of what
the azimuthal pattern was. It turned out to be a sort of deformed cardioid
pattern, barely directional, and the direction of maximum gain was about 30
degrees off. The pattern was similar on both 2 and 70 cm. My conclusion was
that these antennas were useless for weak signal SSB or CW. 

Think about it. How often do you hear the question being asked about the
optimal vertical distance between a 2 and 70cm beam. I don't think anyone
ever answered "zero" to that question.

73,
--Alex KR1ST

-----Original Message-----
From: VHFcontesting [mailto:vhfcontesting-bounces at contesting.com] On Behalf
Of John Geiger
Sent: Monday, April 14, 2014 3:55 PM
To: vhf contesting; vhf at w6yx.stanford.edu; 50mhz; 6meter at yahoogroups.com
Subject: [VHFcontesting] Cushcraft A270-10S (triband VHF/UHF) beam question

I have a question about the Cushcraft 6m/2m/70cm yagi. Every picture I see
of it has the 6m elements horizontal and the 2m/70cm portion vertical. That
wouldn't work for me, I want to use it on 2m and 70cm SSB. It is possible to
mount all 3 bands with horizontal elements?

It looks like it is physically possible, but will it hurt performance, or
will it still work ok that way?

John AF5CC
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