CW Bandwidth (was: [Elecraft] K2 w/KSB CW reverse BFO)

[George, W5YR]

Absolutely correct, Vic, but would you believe that a "discussion" on this
topic once ran for several *weeks* on a newsgroup with one stalwart who
knows what he is talking about trying to convince the rest of the world
that rise and fall times were the key factors in determinging keying
bandwidth. Amazing how quickly some folks forget the Fourier expansion of a
square wave!   <:}

73/72, George    
Amateur Radio W5YR -  the Yellow Rose of Texas
In the 57th year and it just keeps getting better!
Fairview, TX 30 mi NE of Dallas in Collin county EM13qe
K2 #489      Icom IC-765 #2349     Icom IC-756 PRO  #2121


Vic Rosenthal wrote:
> 
> "George, W5YR" wrote:
> >
> > Good arguments can be made, and have been in other forums, that rise and
> > fall times affect occupied bandwidth of CW signals to a large extent,
> > possibly as much or more than mere keying speed.
> 
> I think the rise/fall times are the whole story here, George.  The bandwidth is
> determined by sidebands inherent in the leading and trailing edges of the
> pulse.  The relationship to keying speed is simply that the faster you key, the
> sharper you need to make the waveshape so that the elements don't run into one
> another!  To give an exaggerated example, if you are sending five dits at per
> second and your rise/fall times are greater than 100 ms., then the dits actually
> begin to run together.
> 
> Vic K2VCO