Hi Steve,
You probably measured arriving signals with qsb so you just proved your
method being wrong, otherwise the result would be always the same.
You need to measure and compare the major lobes just outside the near field
to compare antennas.
73
Peter
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Steve
Hunt
Sent: Dienstag, 25. November 2014 00:14
To: Jim Thomson; towertalk@contesting.com
Subject: Re: [TowerTalk] Yagi gain vs rotary dipole.
Jim,
I did exactly that when I was developing the hexbeam. I had a reference
dipole at the same height on a different mast, "pointing" in the same
direction. I A/B switched at 1 sec intervals while listening to a CW
signal. The receiver AGC was off and the gains were adjusted to put the
signal in the linear part of the receiver characteristic. I fed the
audio into a PC sound card and measured the step changes with some audio
analysis software.
Mostly the hexbeam was stronger, sometimes there was no difference, and
just once or twice the dipole was stronger. This is the sort of
distribution I got:
http://www.karinya.net/g3txq/temp/hex_gain.png
Modelling had predicted the hexbeam would be +3.5dBd.
I would never normally have attempted to measure the gain on sky-wave
signals, but someone on one of the discussion groups was adamant that
the hexbeam's gain is significantly higher on sky-wave signals, and I
wanted to prove them wrong!
Steve G3TXQ
On 24/11/2014 16:37, Jim Thomson wrote:
> Has anybody actually measured the gain of a yagi vs something like a
rotary dipole.... at the same height ?
>
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