The noise comes from the RF chain, not the AF. You can prove this by
simply turning down your RF gain and observing that most of it goes
away. Having a higher quality audio stage would accomplish very little
if anything. Most of the white noise comes from the I.F. amps. It is
not as obvioius on the average rice box as it is on the Omni C or
Corsair due to the other noises generated tending to mask the while
noise. It's like driving fancy car and hearing a bit of road noise
while in a cheap car the wind and rattles tend to mask the road noise.
The Omni C is your fancy car and you can hear every little defect
while the TSFTDX-*!#$% is your 72 Pinto.
The Omni C has the selectable audio filters within the agc loop and I
usually leave it set for position #1 which pretty much eliminates all
the IF noise.
Steve N4LQ.
> Hmmm. It just dawned on me -- is the hiss from the RF/IF chain, or
is the
> real culprit the AF output IC or preamp, etc.? If the noise were
being
> generated before the AF gain control increasing the AF gain setting
> wouldn't affect it; but increasing the AF gain control setting would
> improve signal-to-noise ratio in anything AFTER the AF gain control
if I
> am thinking right.
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