Tony Giacometti wrote in
:


I did the measurements in the SSB mode.

This receiver is very quiet with no antenna connected.

I know it is popular to make measurements with no antenna connected
(meaning the antenna jack is left o/c). The measurements are meaningless.

Measurements with a matched load are meaningful, the noise output power
of the receiver is due to the equivalent receiver noise power + the noise
in a matched load.

You will also see discussion of whether receiver noise increases or
decreases when a matched load is disconnected... it varies from receiver
to receiver and it highlights the useless nature of the o/c measurment.

When I tune the preselector for a peak in noise the noise jumps up
noticeably.

What about the AGC setting?


To make a meaningful comparison, the receiver gain must not change
between measurements, so no change in AGC, no change in RF or AF gain,
safest if there is no S meter reading for both measurements.

Turning AGC off doesn't necessarily extend the range of the SSB receiver
where audio output is linearly related to RF input, don't depend on it
unless you have measured its performance.

Owen