Joel Koltner wrote:
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?"


Because that noise power has a source impedance of 100 milliohms, which
is dramatically mismatched to the input impedance of a normal receiver.
This is explained in Wes Hayward's full-length textbook, 'Introduction
to Radio Frequency Design' (now re-published by ARRL).


--

73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek