[Orion] Orion Receiver Audio Background Noise

[Robert Carroll]

The Orion receiver is the best I have used, but there is an aspect of it I
don't understand and don't particularly like.  I think back to some of the
early transistor portable radios-about 1959 or so.  The sound from these
sets was pretty good, but when you turned the volume control fully down so
that you couldn't hear a station there was still a audible shhhhhhhhhhh
noise from the speaker.  With my Orion if I connect a dummy load to the
antenna input I still get a "shhhhhhhhh" which is clearly audible on the
speaker or headphones.  Any real signal input is enough to overcome this
background noise, but to me it is annoying.  When I crank down the audio
gain on my MP and Pro, all audio background noise disappears. With the Orion
I find that when the AF gain gets very close to zero on the bargraph there
is a click and the shhhhhh is gone, but at the 2-3% point it is back and
increases with the AF gain control.  Activating NR removes most of it.
Cranking back the RF gain control lowers it, so I assume it is generated by
DSP activity of some sort.  To me over a period of time on cw using
headphones this background noise is fatiguing. I wonder if this is the root
of some of the "noisy receiver" complaints that appear from time to time.
Has anyone else noticed this? Is it a necessary "feature" of the digital
processing being used?

 

 

Bob W2WG