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[TowerTalk] Log Periodic Antenna recommendation?

To: <towertalk@contesting.com>
Subject: [TowerTalk] Log Periodic Antenna recommendation?
From: W8JI@contesting.com (Tom Rauch)
Date: Mon, 9 Jul 2001 10:57:30 -0400
> M2, Raibeam, Antenna Mart and many others deserve your business who sell
> great products and I'd support them.  New and effective designs are bad
> mouthed for long periods of time until competent evaluators give it a
> clean bill of health.  Large sums of money and time can be invested in a
> new product and killed or sales crippled by the "Army of the Performance
> Misinformed" and does a lot of damage unfortunately without recourse.

There certainly is a lot of unusual antenna science!

One antenna manufacturer, in a QST article, claimed or implied the 
ionosphere does not respond in a reasonably linear way to system 
gain. Besides implying a grossly non-linear ionosphere, they 
"cooked down" performance of other antennas in a graph or 
comparison chart.

Another manufacturer claimed more gain than is possible with any 
combination of spacing and phasing using two elements. They 
"invented" a thing called "critical coupling K=1" to explain how they 
could have gain beyond theoretical limits of a perfectly excited and 
spaced lossless structure.

When asked to check out a 40 meter quad for a friend of mine, I 
asked about gain. The salesman/ designer told me when a dipole 
at the same height would be S-8 the quad was 20 over 9 in New 
Zealand. I thanked him and advised my friend to buy something 
else, because I couldn't get a straight answer.

The common excuse is there is something "special" going on that 
just can't be explained, and that models won't even show how well 
the antenna really works. That's a warning sign of pathological 
science at work!
73, Tom W8JI
W8JI@contesting.com 

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