Reg wrote:
"So we have a generator with open-circuit volts of 300 mV, with an
internal resistance of 1.944 ohms, into an Rx load resistance of 1.944
ohms---."

You lose 1/2 the open-circuit voltage in a matched antenna`s radiation
resistance. 1/2 the voltage in the receiver`s input resistance causes
1/2 the current. Received carrier power is only 1/4, or in other words,
6 db less than twice the voltage would produce were it available across
the receiver`s input resistance.

0.15 volts squared over 1.944 ohms = 0.01157 watts on my Chinese
calculator

Best regards, Richard Harrison, KB5WZI