Topband: dynamic range

[Joe Subich, K4IK]

> My thought is you start with a generator with an output much 
> greater than 50uV, then follow it with an attentuator connected 
> between the generator output and the receiver input. This pads 
> the generator and it sees a load very close to 50 Ohms.  Is 
> this the correct way to go about setting this up?

Yes, the proper way to set up the S-meter would be to use a 
signal generator set to 500uV and a 20 dB inline 50 Ohm 
attenuator.  The 20 dB pad would assure that the generator 
saw (very close to) 50 Ohms no matter what the effective 
input impedance of the receiver and the receiver would receive 
50 uV within a dB or so even if its input impedance were 
significantly different than 50 Ohms. 

> Also, what frequency should be used to calibrate the 
> receiver? As we all know the receiver sensitivity changes 
> from band to band.

Most amateur manufacturers I've seen specify calibration on 
20 meters. 

73, 

   ... Joe, K4IK