Owen Duffy wrote in
:

....
Expected ambient noise level from a lossless antenna in 2kHz at 3.6MHz
should be around -82.9+33dBm or -49.9dBm. The 80m loop gain is about -
47dBi, so expected receive level would be -97dBm which is some 40dB
above your receiver noise floor.

That is wrong, the 82.9dBm was for 2kHz bandwidth, and I should not have
added the 33dB bandwidth factor... it is a double count.

So the receive level would be -82.9 -47 or -129dBm which would be just 10dB
above the receiver noise floor... in the ballpark of what you measured
Tony.

Sorry for the bum steer.

I am still working on a more detailed model, and it will drive the gain
figure downwards a bit.

Owen