[CW] Speed vs Bandwidth

[Gerry Maira]

Gerry Maira wrote:
> 
> Buck wrote:
> >
> > For some unknown reason, I have been bugged lately about the theory I
> > learned 25 years ago that the faster a cw signal is sent, the broader
> > the bandwidth of the signal.  I didn't get my license by learning the
> > questions and answers.  While I am not a CET or equivilent, I have
> > studied electronics and had to get my license by learning theory.  (This
> > isn't a put-down to those who used the q/a method, its my background so
> > readers get a feel for my understanding of electronics).
> >
> > When I studied it, I had no choice but to accept the theory that the
> > signal width (band-width) is actually greater, the higher the speed of
> > the cw.
> >
> > In practice, I see that the more power I receive from a station, ie the
> > greater the signal strength, the greater the tuning band-width that I
> > can receive some noise of interference, as it may be.  However, in cw,
> > whether its a carrier or someone sending 60+ wpm, at s-5 or so, I can't
> > tell the difference between the width of either station.
> >
> > Has anyone actually tested this theory on a spectrum analyzer?  Is this
> > a theory we just have to accept or is there any real basis for the
> > statement.  You folk might have to forgive me, but I can't immagine that
> > there is actually a cw speed that could consume the entire 80 meter ham
> > band.  I can imagine a cw speed that is so fast that on 80 meters it
> > can't be copied reliably but, and maybe I understand it wrongly, I can't
> > think of anything that will key on and off so fast that my rig will
> > actually transmit two or three times the signal width in it's specs.
> >
> > The world won't come to an end if I never understand this, but if
> > someone can explain, I would appreciate it.
> >
> > Thanks
> >
> > Buck
> 
> There is no difference in bandwidth if the only thing changed is the speed of keying.

Just to clarify - By keying speed I mean code speed.