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What is the duty cucle of correctly sent Morse code?

Discussion in 'Working Different Modes' started by M0WAN, Jun 12, 2010.

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  1. M0WAN

    M0WAN Ham Member QRZ Page

    As per title, what is the duty cycle of correctly sent morse code? I would like to know in order to correctly rate and not overrun a PA. I've had a good look on Google but didn't mamage to turn anything up. I suppose I could work it out roughly but this would be a tedious process, and unnecessary if the answer is general knowledge amongst you seasoned CW users. Many thanks.
  2. N0IU

    N0IU Ham Member QRZ Page

    It depends on the bandwidth which is dependent on the speed at which it is sent, and the shape of the keying waveform. Basically the bandwidth increases with increasing speed, and also increases the closer the keying waveform approaches a perfect square wave.

    If you Google "cw bandwidth", you will get tons of information.
  3. M0WAN

    M0WAN Ham Member QRZ Page

    Thanks for the link - that made for interesting reading.

    It also answered my question, in that they illustrated how the word 'PARIS' took up 23 of 50 basic time slots. This translates into just under 50 percent duty cycle for Morse sent at moderate speed, which was the sort of guide to the duty cycle I was looking for.

    I reckon I can safely assume 50 percent for PA dissipation purposes, plus bias considerations, so many thanks. :)
  4. AG3Y

    AG3Y Guest

    The "normal" dot to space between the dots is 50% duty cycle. A "dash" is considered to be three dots long. I seem to recall that the space between letters is equivilent to the length of a dash, and the space between words is somewhat longer than that. Maybe three dashes long.

    It has been quite a while since I actually tried to analyze it. One just develops a rhythm and doesn't think about it after a while. It is just like talking. You don't think of the rhythm when forming a sentence, you just form the sentence, and are done with it!

    Of course, one can either go "heavier" or "lighter", depending on their taste, and change that ratio, but no one is going to complain if you use the "normal" element weighting.

    Don't know if this helps, or not. Hope it does.
  5. WA4OTD

    WA4OTD Ham Member QRZ Page

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