[Elecraft] Recommended AGC settings for separation of signalsin CW pile-ups

Sun Dec 5 12:42:57 EST 2010

It's not NEARLY on frequency.  It's EXACTLY ON FREQUENCY.  I know what
I'm hearing.  I can hear a hertz in the area around my usual 450 Hz
spot.

This problem is getting worse as frequency accuracy is getting to half
a hertz on modern rigs (half a hertz measured on my K3), and people
use packet spots to arrive on frequency.  These people are frequently
EXACTLY on the same frequency. Not close, EXACTLY.  Research by Bell
Labs in the 1930's suggests that with no other clues for the ear to
separate them (as in diversity RX) that 3 to 6db is the minimum
difference to allow the ear to separate two signals on volume alone.
Or stated differently, your ear probably needs something an S-unit
difference to discern two signals exactly on frequency with no other
separation information in the signal blend.

As to the AGC, all the options are what everybody was hugely clamoring
for so everybody could "do it their way."  So you got what you wanted.
The flip side of that is that all these variations have to have a
value set BY YOU. Not by Elecraft, BY YOU.  All you guys that wanted
all this flexibility, stand up now and be counted and defend yourself.

Someone was touting their Orion as having a better AGC.  TenTec went
through the AGC options torture as well. There are those who
SPECIFICALLY abandoned the Orion because they could do AGC better on a
K3.

As best as I can tell, I can set the K3's AGC to mimick any rig's AGC
I've ever operated by picking a set of option values, including my
75A3.  So if the K3 AGC is supposed to be worse than rig XYZ, whose
fault is that?

The truth is that the K3, by offering all the options, has allowed the
complexity of the problem to be exposed and put Elecraft on the
bleeding edge of original development with a responsive company that
will actually try out new stuff that emerges.  One would think you
guys would LOVE that for the unique opportunity it really is.

73, Guy.

On Sun, Dec 5, 2010 at 11:50 AM, Dave Hachadorian <k6ll at arrl.net> wrote:
> This thread is not about copying signals that are separated by
> 100 Hz.  We are talking here about multiple nearly-on-frequency
> callers in a pileup.  In those circumstances, with most rigs, you
> can separate the signals by amplitude, or slight pitch or other
> CW idiosyncrasies.  The K3's agc has a problem dealing with that.
> Signals are compressed together, such that you can't copy anyone,
> unless you reach for the rf gain control.  If you turn agc OFF,
> you have to deal with the crazy AF Limiter.
>
>
> Dave Hachadorian, K6LL
> Yuma, AZ
>
>
>
>
> -----Original Message-----
> From: Hector Padron
> Sent: Sunday, December 05, 2010 9:22 AM
> To: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] Recommended AGC settings for separation
> of signalsin CW pile-ups
>
> Oh well,I don't like to argue anybody or disagree anybody but I
> was at the contest as well and and I could easily separate CW
> stations that were off  between 100 200 Hz with my K3 using the
> 400Hz roofer and the DSP set to 100Hz and also moving the Shift
> acordingly,.no problem at all with the selectivity and also I
> used the great help of the APF as well.
> If it has to be with the AGC or not,these are my settings that
> has been working for me in any case:
>
> AGC DCY.....SoFt
> AGC HLD.....0.05
> AGC PLS.....OFF
> AGC SLP.....0.07
> AGC THR.....007
> AGC-F.........080
> AGC-S.........020
>
> To help in the RX filtering I have set my RX EQ this way:
>
> 0.05 at minus 16
> 0.10 at minus 16
> 0.20 at minus +0
> 0.40 at +3
> 0.80 at +3
> 1.60 at minus 16
> 2.40 at minus 16
> 3.20 at minus 16
> PITCH at 400 (I like to hear better at low pitch)
>
> With these settings my K3 is super selective and have no ringing
> noise even at 50Hz DSP bandwiith.
> In those conditions I can work any contest no matter how crowded
> it will be.
>
> AD4C
>
>
>
>
>
>
>
> "If freedom means something,it is the right to tell others what
> they don't want to hear" –George Orwell
>
> --- On Sun, 12/5/10, Tommy Alderman <aldermant at windstream.net>
> wrote:
>
>
> From: Tommy Alderman <aldermant at windstream.net>
> Subject: Re: [Elecraft] Recommended AGC settings for separation
> of signals in CW pile-ups
> To: elecraft at mailman.qth.net
> Date: Sunday, December 5, 2010, 10:47 AM
>
>
> Bob -
>
> I agree with the observation about the K3's effectiveness  in
> separating
> contest signals in big piles as that was the only thing that
> irritated me
> during CQWW CW contest. I have just started to try and optimize
> the AGC
> settings for large signal conditions and so far, I'm not anywhere
> close yet.
> If I can find anything useful, I will post it here. I certainly
> do hope
> others who may already have optimized their K3 AGC for large
> signal contest,
> will also post their information.
>
> 161,
> Tom - W4BQF
>
>
> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Bob
> Henderson
> Sent: Sunday, December 05, 2010 4:39 AM
> To: elecraft at mailman.qth.net
> Subject: [Elecraft] Recommended AGC settings for separation of
> signals in CW
> pile-ups
>
> CQ WW CW is now over.  We used K3s at P3F this year.  While
> performance was
> generally considered good, some questions were raised over the
> effectiveness
> of the K3 in separating signals in large piles.
>
> Similar concerns appear to have surfaced from other users
> including the guys
> at 9L5VT and C6ATA.  Anecdotal evidence suggests the old TS930
> and TS850
> performed better in such circumstances.  I suspect the AGC
> systems of the
> K3s used had not optimised.
>
> Has collective experience of the K3 contesting community derived
> optimum
> settings for the K3 AGC system in this kind of situation?
>
> Thanks
>
> Bob, 5B4AGN
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