Topband: S-meter Calibration

K8LV1 at aol.com K8LV1 at aol.com
Wed Feb 11 14:44:29 EST 2004


When I posted the measurement data, I really had no agenda. That seems to 
have been supplied by all of the responses. I simply wanted to document it to 
avoid some hand waving that goes on.

However, now I will drop the other shoe. Assuming that the RX input is a 50 
ohm resistor is a mild approximation in comparison with assuming that the 
'generator' driving it has 50+j0 source impedance. Particularly true if that source 
is something as ill-defined as a beverage antenna, which is what most of us 
listen with on 160. The approximations abound and cascade, which is why 
absolute calibration is so futile. What we really want to measure is the value of E 
or H of the incident EM field, which is the only true measure of received power.

73
Eric von Valtier K8LV


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