[Elecraft] K3 CW rise time mod - Definition

[Gary Bartlett VE1RGB]

Terms such as "tightening up key shaping" and "soft keying" and "hard 
keying" are neither used nor defined in the latest issue of the 
Handbook.  Worse, the latest handbook Figure 9.8 states that on-off 
transitions of the RF envelope should follow  a sine-wave curve, so I 
don't quite know what to make of "DSP-generated raised-cosine key 
shaping."  As to Goodman and Garmmer, I wouldn't be able to identify 
what is accurate and should be believed and what is inaccurate and 
should be ignored,  so I don't think I'll go looking for those 
references.  And no, Paul, I'm not trying to be a smart-ass here.  I'm 
just a simpleton trying to decode the language used by people who know 
about such things.

    Pointing me to the Handbook -- which I should have had sense enough 
to do on my own -- did help in that it reminded me that key clicks and 
bandwidth are the issues associated with rise times and curve shapes, 
which is what I was really looking for, and Figure 9.9, if I study it 
long enough, may point me to a decision as to whether or not I want to 
modify ole #95.    Either that, or wait for Al, VE1AWP, up the street 
with his FT1000 to complain about my signal when we both try to contest 
on the same band at the same time!

    Great radio and lots of good people around to help us understand 
it.  Thanks, Paul.

    Gary, VE1RGB


   

Paul Christensen wrote:
>>    I would like to see someone please take this discussion one step 
>> further and define the terms "hard" keying and "soft" keying, and 
>> describe how either an operator or someone listening would be able to 
>> discriminate between the two.
>
> Gary, this topic has been covered in great detail in nearly every ARRL 
> Handbook for at least the last fifty years -- as well as other 
> publications. Some of the most relevant material is covered in 
> articles during the '40s and '50s by By Goodman and George Garmmer. 
> Not all of the material pertaining to "optimum key-shaping" is 
> accurate, but otherwise, the content is still accurate.
>
> Many of us do not like to be held hostage to one rise/fall setting as 
> a "one size fits all" answer to our operating practices. With 
> DSP-generated raised-cosine key shaping, it's now possible to tighten 
> up key shaping at high CW speeds without appreciably consuming 
> additional bandwidth.
>
> Paul, W9AC