[Elecraft] Hearing CW - Fundamental Keying Waveform?

[Dan KB6NU]

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: elecraft-bounces at mailman.qth.net
>> [mailto:elecraft-bounces at mailman.qth.net]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