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LCWO Discussion Forum [Atom LCWO Forum Feed]

This is a simple discussion forum for LCWO users. Feel free to use it for any kind of discussion related to this website.

Thread: Timing of output copy seems to be off

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AuthorText


Posted: 2008-10-30 20:31
Not a big deal. I was doing lesson 11, speed 20/10 and requested 2 minutes. The sending was done in 1:32 seconds.
Administrator


Posted: 2008-10-30 20:47
Yes; there is some silence at the start and the end of the transmission, but also the time of a text varies a bit. When you get a lot of short letters like Es, it's shorter, likewise if the random generator decides for a lot of long letters, it's longer.

Also, the accuracy of the length in minutes gets worse as the ratio of character speed and effective speed increases. With extreme ratios like 100wpm characters, 1wpm effective, the times are completely off...

73, Fabian


Posted: 2008-10-31 04:27
I'm sure calculating the timing is a nightmare. Since its only a relative measure of how much practice to send, you could have time or a text box that requests the desired number of characters regradless of wpm/cpm. Anyway not a big deal - I test software for a living so its hard to at least not point things out ;-)

73, wa2nfn Bill


Posted: 2008-11-02 23:59
I have started to think that the timing is way off. I am under the impression that a "word" is about 5 characters, but I am finding that it delivers the number of 5-char "words" as selected but in HALF the time. I have been using 18/5 speed but it delivers the words in about HALF the time. I changed to 18/3 and 2 minuts - but the 6 5-char groups arrive in under 1 minute.


Posted: 2008-11-03 08:31
Same experience her (see http://www.lcwo.net/?p=forum&t=42 ).

Seems to be apparent only at extreme settings.

I find this however easy to workaround myself by measuring wpm/cpm and entering "wrong" speed/effective speed to get the "right result, i.e. expected number of code groups per minute.

Regards,

Gerd.


Posted: 2008-11-03 20:15
Yes, I think that the word rate has failed to allow for the data rate, i.e. the gaps between characters don't change when the data rate is changed.


Posted: 2008-11-05 06:01
I have not done the math - but would hope the timing is close, since its what we all are uinsg as a measure of out skill (assuming 90% or better copy). A "word" is a set of characters taking 50 units (dit=1, dah=3) the standard is the word PARIS since this word plus the spacing to the next word nicely comes to 50 units of time. If wpm and cpm are the same you can figure out how many times you shold get "PARIS" in a minute. If the wpm and cpm differ then you need to adjust for that - see "Morse Code" in wikipedia.com. Then a few tests can be run and see how far off it is. I think this is why most tutors use a wpm but don't show a running clock. They instead calculate the total number of units needed to achive your "minutes" of copy, and then as the random number generator creats charaters, the count of units for that char and the spacing have to be deducted until the time is very close. An alternative is wat I suggested and that is asked for a char count e.g 100, 500 etc at the desired speed.

Just my opinion, the tool is great - but I'd like to know that my 90% at speed x is withing a percent or so of reality.

WA2NFN
Bill


Posted: 2008-11-05 16:03
FYI I did do the straigt forward test using the text to CW feature sent "Paris" 10 times at wpm/cpm=10 and it ran in exactly 1 minute! So the skewing must be as suggested in the accounting for a cpm differing from wpm and not filling out the time correctly. So you can at least confirm your real code ability as used to be tested in the US by the FCC with the wpm=cpm.

Cool
Wa2nfn

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