[Orion] V2.059d Vs. v1.373b5 Noise Reduction Code + My experiences with 1.373b5

[Joe Giacobello]

Bill, thanks.  I remember Sinisa's paper, but I never had much luck with 
it.  Nevertheless, I'll reinstall 1.373b5 and try exactly what you 
suggest.  There is no doubt that there was too much RF gain.  However, I 
did manipulate the attenuation, RF gain, and threshold and I would never 
use the preamp on 40M anyhow.  However, I didn't manipulate them in an 
orderly fashion such as you have described.  I'll let you know how I 
make out.

Thanks for your help.

73, Joe

73, Joe

Bill Tippett wrote:
> K2XX:
>  >I replaced 2.059d with 1.373b5 last night and the change in performance
> was both dramatic and negative.    There was an enormous increase in RF
> gain, which was further increased when invoking NR.  I tried
> manipulating the Threshold, Decay, Attenuator and NR setting without
> much improvement.  To make 40M CW even marginally listenable, I had to
> use 12 dB of attenuation.  The NR seemed to act properly with the
> attennuation.  The Threshold setting seemed to have no effect and there
> seemed to be a non-linearity in the RF gain control.
>
>          Almost certainly an indication RF GAIN is set too high.
> Also, AGC Threshold and RF GAIN are now linked in all V1
> versions following 1.371.  To set RF GAIN correctly:
>
> 1.  Set AGC Threshold = 1 uV for all bands, all AGC options.  Set AF 
> GAIN to mid-scale.
> 2.  Tune to an area of the band with antenna connected but no
> signals.
> 3.  Adjust the following, in order, until you cannot hear band
> noise when switching between no antenna and your antenna (e.g.
> ANT 1 vs ANT 2 with nothing connected to ANT 2):
>
> a.  Preamp Off
> b.  Attenuator (6/12/18 dB)
> c.  RF GAIN
>
> 4.  When you can no longer hear band noise, then increase RF
> GAIN until it just becomes comfortably audible (but not beyond
> that point).
>
>          Anytime I hear people complain about Orion being
> "noisy", it is usually a sure indication there is too much
> gain in their setup.  The above is adapted from a paper
> Sinisa YT1NT wrote below, but it was prior to 1.372 when
> Threshold and RF GAIN were integrated into one control.
>
> http://www.geocities.com/va3ttn/UsingOrionRX.pdf
>
>                                          73,  Bill  W4ZV
>
>
>
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