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

[k8vf_mark at centurytel.net]

Gents, if I go "backward " to 1.37xxx from 2.056, will I lose the sweep 
feature if the sweep mod has been done?

Thanks,
Mark


----- Original Message ----- 
From: "Joe Giacobello" <k2xx at swva.net>
To: <k2xx at swva.net>
Cc: <orion at contesting.com>; "Bill Tippett" <btippett at alum.mit.edu>
Sent: Monday, September 25, 2006 1:12 PM
Subject: Re: [Orion] V2.059d Vs. v1.373b5 Noise Reduction Code + My 
experiences with 1.373b5


> Bill, I just wanted to let you and the list know that I had a chance to
> check out your procedure for RF gain, etc. adjustment this weekend on FW
> 1.373b5.  There was a vast improvement in performance, although I didn't
> spend as much time as I wanted to with it, and I'm still evaluating.
>
> I wound up using 18 dB of attenuation and the RF gain at 60-80 with a
> threshold of 1.02 uV on 30 and 40M CW.  When I invoked the NR, the noise
> (gain) did increase, but readjusting the RF gain got it back under
> control.  I haven't really checked the settings out on very weak sigs,
> etc, but there's no doubt that a vast improvement was obtained.
>
> I did have to do a master reset (after the initial reset after loading
> the new FW) when I lost all output power.  Others have reported similar
> glitches with 1.37x FW.  I had occasionally observed power output, mike
> gain or audio output losses with 1.37x myself.
>
> Another issue:  If the NR works by narrowing the receive bandwidth in a
> manner similar to manually reducing selectivity of the filters (I
> presume that the NR uses different algorithms for CW and SSB.), why have
> an NR at all except for its automatic feature?   Interestingly, I had
> reported that FW 2.059d seem to clip the signals when using NR at a "1"
> setting.  However, I also noted that the clipping could be minimized by
> very carefully centering the sig in the passband, which seems to support
> the argument that NR works by reducing BW.  OTOH, with weak sigs no
> amount of centering helps.
>
> 73 and thanks for your help.
>
> Joe
> K2XX
>
> Joe Giacobello wrote:
>> 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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>>>
>>>
>>>
>>>
>>
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