http://elecraft.85.s1.nabble.com/K3-in-a-cw-pileup-needs-work-tp4523884p4546142.html
> operating range. If they do, a -99 threshold is a -109
the roofing filter is not the way to do it. If you want to
IF - preferably divided between the first IF and 2nd IF.
that be reached with preamp on, preamp off or attenuator on.
... Joe, W4TV
> -----Original Message-----
> From:
[hidden email]
> [mailto:
[hidden email]] On Behalf Of Guy
> Olinger K2AV
> Sent: Monday, February 08, 2010 1:49 PM
> To:
[hidden email]
> Cc:
[hidden email]
> Subject: Re: [Elecraft] K3 DSP AGC Question
>
>
> It may be a dance, but hopefully careful intelligent musing
> over the matter is convincing people that they should get the
> ambient well down in the analog-to-digital converter (ADC)
> operating range. If they do, a -99 threshold is a -109
> threshold, and further backing off RF gain can make it a -119
> or -129 threshold as far as the ADC is concerned, and
> headroom is being used for what headroom should be used for.
>
> One thing for sure, there has not been a good-enough
> presentation of what is going on, and people really don't
> seem to get it. For something that is plain indisputable
> physics, people are still running PRE and max RFgain on 80
> with fast AGC, and are honestly dismayed and confused about
> the inevitable outcome, incorrectly blaming the rig for being
> natively noisy, no-work NR and NB, filter "ringing", unable
> to pull signals out of noise, and more.
>
> Maybe the variable gain by band in the MP (with a menu
> override) was really a better strategy for a default. This
> same issue dogged Orion owners, and by the chatter a lot of
> them never understood either.
>
> There IS something entirely separate with the headphone audio
> and HI-Z headsets, high volume levels, maybe a sharp
> saturation point, and mush, just haven't nailed it yet.
>
> 73, Guy.
>
> On Mon, Feb 8, 2010 at 12:01 PM, Joe Subich, W4TV
> <
[hidden email]> wrote:
> >
> >
> >> Likely? I don't know.
> >
> > Likely is a better choice since raising the AGC threshold
> seems to be
> > the primary goal of much of the "PRE/ATT/RF Gain dance" we've seen
> > recently.
> >
> > The hardware AGC (HAGC) would seem to provide an ultimate limit on
> > level to the ADC - unless the ADC can't handle the
> transient peaks -
> > so a higher threshold for the DSP derived AGC would be
> helpful in many
> > ways.
> >
> > 73,
> >
> > ... Joe, W4TV
> >
> >
> >
> >
> >> -----Original Message-----
> >> From:
[hidden email]
> >> [mailto:
[hidden email]] On Behalf Of Lyle Johnson
> >> Sent: Monday, February 08, 2010 11:24 AM
> >> To:
[hidden email]
> >> Subject: Re: [Elecraft] K3 DSP AGC Question
> >>
> >>
> >> Hello Joe!
> >> > Assuming that the threshold values have not changed in a
> major way
> >> > since Jack's measurements, would it be possible to
> extend the range
> >> > of threshold values - say to AGC THR=016 at about -80dBm
> (assuming
> >> > 2 dB per step)?
> >> >
> >>
> >> Possible? Yes.
> >>
> >> Likely? I don't know. There are a lot of side effects
> that happen
> >> when the threshold is raised...
> >>
> >> 73,
> >>
> >> Lyle KK7P
> >>
> >
> >
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