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Re: [TowerTalk] steppIR Gain--test method

To: <jimjarvis@ieee.org>, <towertalk@contesting.com>
Subject: Re: [TowerTalk] steppIR Gain--test method
From: "Tom Rauch" <w8ji@contesting.com>
Reply-to: Tom Rauch <w8ji@contesting.com>
Date: Wed, 16 Mar 2005 14:08:26 -0500
List-post: <mailto:towertalk@contesting.com>
> If I recall correctly, Mike and Jim have their own range,
> with the unit under test on one tower, and an HP spectrum
> analyser connected to a dipole on another tower,  many
> wavelengths distant.  Tower heights were on the order of
> 60'.  A calibrated attenuator was used with the SA.

Well, the many wavelengths distant is already a problem.
Measurements would be much more accurate just out of the
near field. I don't know why anyone would measure an antenna
in the null of the pattern, and when a horizontal HF antenna
is at 60ft and the path is long there is a null along the
horizon! Bad measurement protocol.

Measurements would also be more accurate with a directional
antenna at the receiver also, and a good meter instead of a
spectrum analyzer.

Measurements like this are always a problem. Look at the
silly claims of the RAIbeam and that little two element hex
quad thingy. It's commonplace that measurements made in test
ranges that aren't really test ranges are a few dB off.

> Theoretically, the steppIR could be a bit better
> than a canonical yagi...in practice, it's hard to tell,
> because the differences are too small to matter.

Bingo....and probably too small to measure accurately also.

73 Tom

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