On Sun, 10 Apr 2005 09:23:19 -0500, Tom Ring
wrote:

I wouldn't bet absolute values are on the mark, but an antenna measured
against itself was reproducable.

Hi Tom,

But the point of accuracy, even reproducible accuracy, requires a very
absolute source to compare against. Sometimes that absolute is quite
simple to achieve, but now you have upped the ante to 0.1dB. This
implies a measurement accuracy of at least three times better; which,
in turn, means you have access to a standard that can discern 0.8%.

To say you test the antenna "against itself" does not really say much
when it comes to power and gain. That is no benchmark. The
presumption here is that you have an external source of power that is
constant. This then raises the same question. Over a span of time,
what guarantees this degree of accuracy? By what method is it
confirmed? That source's "absolute" power level needn't be an issue,
but there is no way to escape casting that "absolute" requirement into
another standard to confirm the fact of its stability.

73's
Richard Clark, KB7QHC