K3 CW Auto Spot in 3.30 with NR turned on

[Mike K2MK]

I've been playing around with the NR filters in 3.30 and I have found that
the CW auto spot feature is not working for all of the NR settings. As an
example, I tried the dash "2" range in all 8 "F" settings. The auto spot
function works perfectly on:
F1-2
F2-2
F3-2
F4-2
F5-2

It does not work at all (it doesn't even try) on:
F6-2
F7-2
F8-2

I usually have the CWT threshold at 2 but I also tried it at 1 through 4
with the same results.

73,
Mike K2MK

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[Mike K2MK]

I may have answered my own question. The signal amplitude drops with the
higher "F" settings and the dancing bar in the CWT display disappears more
quickly as I tune off frequency. When there is no visible dancing bar the
auto spot fails to work. There is no problem with stronger signals or if I
increase the filter bandwidth. My initial findings were with a 50Hz filter
bandwidth.

73,
Mike K2MK

--------------------------------------------------
From: "K2MK" <[hidden email]>
Sent: Wednesday, September 09, 2009 5:17 PM
To: "Elecraft Reflector" <[hidden email]>
Subject: K3 CW Auto Spot in 3.30 with NR turned on

> I've been playing around with the NR filters in 3.30 and I have found that
> the CW auto spot feature is not working for all of the NR settings. As an
> example, I tried the dash "2" range in all 8 "F" settings. The auto spot
> function works perfectly on:
> F1-2
> F2-2
> F3-2
> F4-2
> F5-2
>
> It does not work at all (it doesn't even try) on:
> F6-2
> F7-2
> F8-2
>
> I usually have the CWT threshold at 2 but I also tried it at 1 through 4
> with the same results.
>
> 73,
> Mike K2MK

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[KK7P]

> I may have answered my own question. The signal amplitude drops with the
> higher "F" settings and the dancing bar in the CWT display disappears more
> quickly as I tune off frequency. When there is no visible dancing bar the
> auto spot fails to work. There is no problem with stronger signals or if I
> increase the filter bandwidth. My initial findings were with a 50Hz filter
> bandwidth.
>  

As mentioned elsewhere, the F5-x through F8-x mix some unprocessed audio
with processed audio.

Because the delay through the NR filtering is not deterministic,
depending on pitch and other factors, you may notice an apparent boost
in signal level at your chosen pitch, or a definite decrease in audio.  
The CWT is using audio information, so the observation you make is
consistent with how the overall system works.  A different pitch may
work differently at NR settings in the F5..F8 range.

In general, I suggest the use of F1..F4 for CW, especially if you intend
to use the autospot feature.

73,

Lyle KK7P

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[k6dgw]

K2MK wrote:

> My initial findings were with a 50Hz filter bandwidth.

I'm not sure, but I think the BW of a 30 wpm CW signal such as you will
hear in contests exceeds 50 Hz.  The code elements pretty much run
together at that BW for me, and I really can't discern much.

And you're right, my autospot doesn't work unless the CWT bar is
moderately stable, regardless of NR settings.

I was struck by the fact that I can even set my radio for 50 Hz BW!  I
wonder what the BW was on my Drake 2B with the Q-mult set just below
oscillation?  Things sure have changed.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2009 Cal QSO Party  3-4 Oct 2009
- www.cqp.org
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