"Joel Koltner" wrote in
:

....
But the loss resistance of the antenna itself is still contributing
kTB, right?

Yes... but summing the contributions isn't trivial.

An alternative view is to consider the contribution of conductor loss and
other losses in the antenna structure and feed, and treat the system as
an ideal (lossless antenna) with a specified 'feed loss'.

My observation is that convention is the use the antenna connector or w/g
flange as a reference point for such calcs. It may even be laid down in
standards... but I am not sure. Someone else may know?

Notwithstanding that convention, I note the VK3UM tools seem to make
their reference point a point on the space side of the antenna. That
would give rise to a slighly different G/T figure.


If I take a small loop of wire that has, say, a 100 milliohms of
resistance, it still generates kTB watts of thermal noise power. Why
isn't this a "problem?"

I don't know what you mean by "problem". I have explained above that it
should be accounted for, and a method.
....
A discussion of noise sounds like a good topic for a ham fair...
technically there's little more complex than algebra (i.e., it's
accessible to pretty much everyone), but plenty of room for
misapplication.

I haven't been to ham fairs in your country, but here there are mostly
focussed on exhanging junk (selling the junk bought at the last fair, and
buying some different junk to sell at the next fair).

Noise is dealt with pretty well in text books, but text books aren't as
popular as mags.

Complicating this in the real world is that receivers aren't perfectly
linear, and measurements in a shielded room often have limited relevance
to real life performance where the 'noise' due to intermodulation
distortion is a significant issue... especially with a trend to avoiding
front end loss (noise) by ditching front end selectivity.

Noise is an interesting topic.

I have just discovered an Agilent AN which discusses uncertainty in noise
measurement. I am about to compare it to my proposition of a statistical
estimate of noise measurement (sampling) uncertainty, see
http://www.vk1od.net/measurement/noise/nmu.htm .

Owen