On Tue, 26 Apr 2005 00:04:02 -0700, Richard Clark
wrote:

On Mon, 25 Apr 2005 14:48:38 -0700, Wes Stewart
wrote:

It may come as a surprise to our correspondent who likes to disparage
"gurus" that "standard-gain" antennas are widely used as reference
standards. To head off the question of how the standard gain is
determined, that is done by testing three "identical" antennas in
pairs; each one against the other two, with one the source and the
other the receiver. A bit of algebra and you have the gain of each
one individually.

http://www.mi-technologies.com/literature/a00-044.pdf


Hi All,

The method described by the paper offered above is a commonplace of
Metrology called "Reciprocity." I have calibrated precision
microphones against this method, and the error math offered is
consistent with my experience (much less the actual values offered as
examples).

It is also a method used for determining the phase noise of low noise
oscillators.


As an aside, this method is also as old as the pyramids - literally.
The Egyptians planned their blocks of granite to have nearly flat
faces to within 10s of microinches using three blocks, by abrading one
against the other and then rotating their positions.

Accuracy is far more a matter of protocol or technique than it is
about a ruler (or other scale).

73's
Richard Clark, KB7QHC