Cecil, W5DXP wrote:
"But the information in a received signal can be had while consuming
very little of the received signal`s power."

Very true, but with AM, or even with weak FM signals, below the "FM
Improvement Threshold", the modulation recovered varies directly with
the strength of the received carrier

Receiver alignment instructions often advise using a modulated signal
from the generator which is weak to ensure operating in a region where
there is a dB to dB relationship between the received carrier strength
and the demodulated signal strength.

You can probably hear Neal Boortz on Aggieland`s 1620 kHz without a
receiver.

Best regards, Richard Harrison, KB5WZI