[R-390] Input impedance of R390A

[DJED1@aol.com]

Sorry, but you're not quite right.  The best power transfer is always when 
you have a conjugate impedance match.  You might get twice the voltage with a 
much larger Rx impedance, but the power delivered to the Rx is voltage 
squared over R, where R is the Rx input resistance.  R must be much greater 
than 50 ohms to double the voltage.  Try a few examples.  The noise power 
from the antenna scales the same as the signal power from the antenna, so no 
benefit to S/N.  Sometime you can get a better NF by mismatching the antenna, 
but this depends on the details of the Rx first stage.
Ed