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[TowerTalk] Antenna Measurements

To: <towertalk@contesting.com>
Subject: [TowerTalk] Antenna Measurements
From: k6ll@juno.com (k6ll@juno.com)
Date: Sun, 20 Jun 1999 11:23:09 -0600


On Sun, 20 Jun 1999 11:01:55 -0400 "James P. Cassidy"
<107770.3462@compuserve.com> writes:
>
>Just a non technical idea about the performance tests, if there was 
>some
>serious flaw in the methods it would seem that there would have been 
>others
>beside the Moseley that showed poorly.  And the results don't show 
>that
>only one manufacturer had the only good performers.
>73 Jim KI7Y

The KLM KT-34XA didn't get a fair shake in that report either.
In addition to the range layout problems, there was apparently
something defective in the KT-34XA used for the
report, causing high swr, NEGATIVE gain and NEGATIVE front to back
ratio in the phone band.

After the initial findings were presented on Towertalk, I
corresponded briefly with the authors, and compared swr and
front to back measurements taken at my QTH with those presented
in the report. The two sets of measurements are markedly different.
Even though my xa has a two element 40 meter beam 6 feet above it,
the swr was much flatter on mine, and front-to-back tests with a
local ham showed f/b readings of 8 to 18 dB across all of the three
bands.

The local ham used for these tests (W7WW) has an antenna setup
identical to mine, and his swr and f/b characteristics match mine
very closely.

I don't have any means of measuring gain, but let me offer the
following anecdotal evidence. With the XA at 48', I recently worked
2254 QSO's in the wpx ssb contest on 15 meters, including 756 EU and
575 Asia. I would conclude from that result that the gain in the phone
portion of 15 meters is considerably greater than zero.

Dave Hachadorian, K6LL
Yuma, AZ
K6LL@juno.com



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