[CW] We agree - Speed vs Bandwidth

[David J. Ring, Jr.]

W5YR wrote:

Grab your 2003 ARRL Handbook and look at Fig. 12.21 on Page 12.13 - I
imagine that the 2004 and 2002 books have the same content in about the same
location.

Fig. 12.21 is a graph that relates bandwidth to rise/fall time. Keying speed
does not enter into the graph at all for the spectral width determination.
It does indicate the maximum keying rate for a K=3 and a K=5 circuit for a
given bandwidth. Nowhere in the material on CW keying could I find any
mention of keying rate influencing bandwidth.
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I really wold like to see what they say for maximum keying rate at K=3 and
K=5 - can you post that?

I agree with you - and your observations agree with me! - the bandwidth goes
up with code speed, but the bandwidth is much more affected by the wave
shape.

So - we've exhausted that interesting topic.  We agree!  How boring!

I might make a sound file and feed it into my IC-756PRO and change the
"voice rate" as I mentioned - that would be a hoot.  I am sure the bandwidth
would go up with the voice rate pulses - so we could have a new thread about
bandwidth goes up when you talk fast (or at least if you make faster
pulses!)  But we need a new email reflector - how about "CW guys who think
they're SSB operators" email list?

George, you can find the relationship between keying speed (baud or baudot
rate) and bandwidth here on the ITU web site:

http://life.itu.ch/radioclub/rr/sm1138.htm


AMPLITUDE MODULATION
1. Signal with Quantized or Digital Information Continuous wave telegraphy,
Morse code Bn = BK
K = 5 for fading circuits
K = 3 for non�fading circuits

25 words per minute; B = 20, K = 5  Bandwidth:100 Hz

Telegraphy by on-off keying of a tone modulated
carrier, Morse code Bn = BK + 2M
K = 5 for fading circuits
K = 3 for non�fading circuits

25 words per minute; B = 20, M = 1 000, K = 5
Bandwidth: 2 100 Hz

73

David Ring, N1EA