"Owen Duffy" wrote in message
...
An antenna's feedpoint impedance comprises radiation resistance and loss
resistance.

OK.

Radiation resistance is a virtual resistance and does not contribute
thermal or Johnson noise.

Certainly, agreed.

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

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?"

Hams tend to not use G/T.

If doesn't seem like "receiver factor" (input intercept point/noise figure)
has caught on much either.

By and large, although lots of hams express an interest in weak signal
working, they aren't very interested in noise... which is a key parameter
determining whether a signal can be copied.

I realized awhile back that noise is the primary factor that limits how far
you can transmit a signal and still recovery it successfully. (Granted, these
days it's often phase noise in oscillators rather than the noise figures in
amplifiers that determines this, but still.)

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'm learning a lot here...

---Joel