RE: Hearing CW - Fundamental Keying Waveform?

Posted by Don Wilhelm-3 on Sep 20, 2006; 5:31am
URL: http://elecraft.85.s1.nabble.com/Hearing-CW-Fundamental-Keying-Waveform-tp393945p393948.html

Darrell,

That has ben dropped from the more recent handbook (does not appear in my
2005 edition).
I am going 'out on a limb' here by saying that this stems from the concept
that 'some keyclicks are good' philosophy.  Sidebands on a CW signal are the
result of the keying shape, and there is more to it than just the rise and
fall times - there is the rounding at the corners to consider too.

I have heard many an operator state that 'hard keying' will get you through
a pile-up better.  While that may be true, it certainly is not 'neighborly'.

I am glad to see that this statement does not appear in the more recent
handbooks.

73,
Don W3FPR

> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]]On Behalf Of Darrell Bellerive
> Sent: Tuesday, September 19, 2006 6:08 PM
> To: Elecraft List
> Subject: [Elecraft] Hearing CW - Fundamental Keying Waveform?
>
>
> The recent thread on filter settings and hearing reminded me of a
> question I
> would like to get an answer to.
>
> In the ARRL 2001 Handbook on page 15.7 we find:
>    "The dots and dashes of a CW signal must start and stop
> abruptly enough so
> we can clearly distinguish the carrier's presences and absences
> from noise,
> especially when fading prevails. The keying sidebands, which sound like
> little more than thumps when listened to on their own, help our brains be
> sure when the carrier tone starts and stops.
>    It so happens that we always need to hear one or more harmonics of the
> fundamental keying waveform for the code to sound sufficiently crisp."
>
> What is meant by "the fundamental keying waveform"?
>
> How do we take "the need to hear one or more harmonics of the fundamental
> keying waveform" into account when setting up the IF and audio filters?
>
> 73,
>
> Darrell  VA7TO  K2 #5093
>
> --
> Darrell Bellerive
> Amateur Radio Stations VA7TO and VE7CLA
> Grand Forks, British Columbia, Canada
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