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Topband: Peer Review

To: topband@contesting.com
Subject: Topband: Peer Review
From: Jim Brown <jim@audiosystemsgroup.com>
Reply-to: jim@audiosystemsgroup.com
Date: Tue, 31 Jul 2012 17:58:02 -0700
List-post: <topband@contesting.com">mailto:topband@contesting.com>
On 7/31/2012 4:13 PM, W0UCE wrote:
> One aspect of the K2AV FCP is KISS.  However, experimenting with change of
> components and proven architecture should anyone opt to do so will produce
> unfavorable results.

Jack,

"It seems to work good in the places it's been tried" but has never been 
compared in a disciplined manner to something of known performance is 
hardly "proven architecture."  Guy has done some excellent engineering 
here, and published it.  Now he's getting some serious peer review, with 
suggestions for possible variations on his work. That's how the "state 
of the art" progresses.  From where I sit, it appears that the most 
important aspects of his design are the compact dimensions and the field 
cancellation in the dirt, not the transformer.

As an example of this peer review process, Rudy Severns, N6LF, published 
some excellent and disciplined work several years ago on his 
measurements of slightly elevated radial systems for a 40M vertical. 
That work showed that, on 40M, four radials elevated only a foot or two 
were nearly equivalent to many long radials on the ground (he set up 
those and many other conditions and MEASURED the field strength).

When I tried to scale his hypothesis to 160M (that is, multiply the 
radial heights by a factor of 4x) on an antenna I had built, I could not 
duplicate his result -- that is, the gain of the antenna was at least 
3dB less than I had expected.  I discussed this over dinner this spring 
with Tom Schiller, N6BT, who has also done a lot of work with radials 
and verticals for 160M. He observed that you can't simply scale the 
radial height by the difference in wavelength because "the earth is very 
different at 160M as compared to 40M, and the radials must be much 
higher." When I asked him "how high," he suggested 16 ft.  This summer, 
with a lot of help from W6GJB, I got them up to at least 16 ft for most 
of their length, and preliminary testing suggests that I'm now getting 
the gain I had hoped.  When I've got more performance data, I'll publish 
it.

Peer review is a wonderful thing.  It is an important part of the 
scientific method.  I've learned a lot by publishing what I think I know 
and having folks fill in my weak spots.

73, Jim K9YC
_______________________________________________
UR RST IS ... ... ..9 QSB QSB - hw? BK

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