[GreenKeys] Computing The Speed Of CW

[Bob McConnell]

Jeffrey D Angus wrote:
> hunybuny at eskimo.com wrote:
>> Here is a rough example of the speed -vs- the clock times.
>> The higher speeds may be off because the way I'm finding
>> the clock speed is to key "dits" on my rig's keyer and
>> then changing the interrupt speed on the computer until
>> they match.
> Ok, a few "basics" first.
> 
> Dit = 1
> Dah =3
> Space between a dit and a dah =1
> (Might be a bit sketchy here)
> Space between letters = 2
> Space between words = 4
> 
> And if I remember right, the standard "one word" is paris.
> So .--. .- .-. .. ...
> Should be a total of 48 (including the between word space)

Even in speed reading, the word count of a text is based on five letters 
and a space. That's pretty close to average in typical American prose.

> 
> This assumes perfect machine code, not somebody sending
> 20 WPM characters at 10 WPM spacing.

I believe that speeding up the characters but not the spacing is called 
Farnsworth (sp?) timing, and it is a standard practice on many code 
tapes and programs. It can make it easier to move to the next level when 
first learning the code. But to do it you need two timers, one for the 
actual bits and a second to trigger the next character.

There are any number of old CW programs around the Internet that include 
source code that may be freely used, or simply read and studied. Google 
can find some of them for you. And I know most systems have better 
timers available than the clock interrupt. But a lot depends on what OS, 
compiler and libraries you have available. To run something like this 
under Unix or Linux, I think you would need to have the real-time 
extensions compiled into the kernel.

Bob McConnell
N2SPP