[Elecraft] K3: Optimizing TEXT DECode for CW

[n4lq]

I tuned in a couple of guys on 40m tonight who were going between 50 - 55 
WPM. I set the decode to 30-90 but it wouldn't decode much of anything 
except a few words now and then. Signals were very strong. No amount of 
tweaking the RF gain or bandwidth helped. No biggie though. Mixw couldn't do 
it either. My ears did fine. Fast code seems to take a bit of time to sync 
up and as soon as the op skips a beat or something, it seems to loose track 
of what it's doing.
Steve Ellington
N4LQ at insightbb.com
----- Original Message ----- 
From: "KM5Q" <km5q at mac.com>
To: <elecraft at mailman.qth.net>
Sent: Friday, May 23, 2008 12:10 AM
Subject: [Elecraft] K3: Optimizing TEXT DECode for CW


> The K3 TEXT DEC system works well on CW signals that are above the
> noise level, but to use it for weaker signals and noisy conditions
> requires some understanding and technique. Here's what I learned.
>
> The decoder gets its signal from the same trigger as the CWT indicator
> bar. See for yourself -- When your display is in CWT mode, play with
> the RF gain so the CWT bar goes on and off. The moment it disappears,
> the decoding stops. As soon as the CWT bar flickers with noise, the
> decoder TRIES  to read the on/off signal. If the CWT bar is responding
> to clean code, you will get good text. If it isn't code,
> unfortunately, the decoder tries anyway, and produces junk text.
>
> If the CW signal is audible but is not stronger than the noise, the
> CWT bar will flicker from the noise AND the CW, and the decoder will
> show too much junk. Once you accept that, you can reduce frustration.
>
> To minimize junk text from QRN, hold TEXT DEC, then adjust threshold
> (thr ...) upward until it "squelches" the CWT bar. Now, The text
> decode will work if there is CW signal above the noise.
>
> But now, set the threshold a little lower, slightly too sensitive.
> This will allow for varying conditions. When noise works the CWT bar,
> reduce the RF GAIN until the bar disappears. This is how to fine-tune
> the threshold quickly.
>
> If you get static crashes or other erratic noise triggering the
> decode, don't let  "IISKSK IEN SKSK" distract you.  Watch the CWT bar.
> Let THAT tell you when to watch the text -- when it LOOKS like code
> rather than noise.
>
> Maybe future firmware will improve the decoder so it will ignore
> noise, but for now, this is the best way I have found to use it.
>
> Windy KM5Q
> Santa Fe, NM
> K3 #764
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