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

Mon Nov 4 18:30:59 2002

to w5yr. do you remember back in 1979 wb5oxz yann the little frenchman from 
garland??? i am now F6HFE on the riviera.

>From: "George, W5YR" <[email protected]>
>To: Vic Rosenthal <[email protected]>
>CC: Elecraft <[email protected]>
>Subject: Re: CW Bandwidth (was: [Elecraft] K2 w/KSB CW reverse BFO)
>Date: Mon, 04 Nov 2002 17:20:00 -0600
>
>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
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