Posted by
Karl Larsen on
Sep 21, 2006; 1:21pm
URL: http://elecraft.85.s1.nabble.com/Hearing-CW-Fundamental-Keying-Waveform-tp393945p393949.html
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'.
>
Hi Don, I recall a lot of years ago a really good DXer used a
measured amount of chirp on his signal. It was not bad but it was
distinctive. He was a DX station often and you knew his signal in an
instant.
It was back when a radio transmitter had a crystal holder and we
were all building a VFO with some degree of success. My VFO was about
the size of a K2 and it was mounted on rubber to eliminate mechanical
noise. Had to build a voltage regulater with a OB2 that made a sort of
regulated 150 volts for the vfo tube plate. It worked great.
73 Karl K5DI
> 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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>
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