This discussion is very interesting to me. I hate copying stations
whose keying isn't sharp enough. The dits and dahs seem to blend
together. It seems to me that with all the DSP power that modern rigs
have, there should be a way to "sharpen up" a CW signal to make it
more intelligible. I'm copying this message to my friend VU3RDD, who
is a DSP engineer, to see what he might think about this.
73!
Dan KB6NU
----------------------------------------------------------
CW Geek and MI Affiliated Club Coordinator
Read my ham radio blog at www.kb6nu.com
LET'S GET MORE KIDS INTO HAM RADIO!
On Sep 20, 2006, at 12:31 AM, Don Wilhelm wrote:
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: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] 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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