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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: effective speed

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AuthorText


Posted: 2010-02-13 21:33
Hi,

first of all many thanks for creating this wonderful page. I am really delighted by its features, especially the statistics are wonderful!

After a break of about 15 years I am trying to get back into cw. I played a bit around with RufZ until I came across this page.

I find the effective speed to be a bit on the high side. I know I've got a fast computer, so I had to turn the speed quite a bit :-)

I selected the code groups with some custom characters, the character speed was fixed to 20 wpm for all tests, and I only changed the effective speed. The practice length was supposed to be 1 min.

eff speed setting sesson time
20WPM 1:30
10WPM 0:56
5WPM 0:38
5WPM (paris) 0:32 ~9WPM

The option to transmit "vvv" at the start was also switched off. Apparently x WPM mean x code groups to be send, regardless of time.

I guess there is some uncertainty in the calculation :-)

Also the steps of 1 wpm seem to be a bit coarse at very slow speeds. I tried 4.5 but without effect.

Cheers,
Chris


Posted: 2010-02-13 21:55
I think my custom character set was very unrepresentative, so I did a few more test with the "paris" characters:

Char speed - effective - time
10WPM - 10WPM - 0:56 (OK)
20WPM - 20WPM - 0:58 (OK)
20WPM - 10WPM - 0:40 (15WPM)
20WPM - 5WPM - 0:32 (~9WPM)

Thus I conclude that the character speed is fine, only the effective speed setting is a bit on the fast side.

Chris
[deleted]

Posted: 2010-02-13 22:56
Chris

A speed of 20 wpm and 20 wpm effective means per international agreed definition that the shortest morse pulse (the sound duration in time of a dit) is 6/5 divided by 20 second long.
In general n words per minute: then a dit sound is 6/(5n) s Example: 20 wpm ditsound 60 ms.

This means of course that the number of characters transmitted with 20 wpm depends on the type of character. Callsigns or random distributed character occurances do not have so many e and i as plain text has; and a lot more X and Q and figures. So when you sent callsigns with 100 cpm (characters per minute)= 20 wpm, you end op with significant less callsign characters per minute than 100.

An effective speed of 10 wpm means then that the letterspacings and wordspacings are made longer such that you keep the shortest dit length the same (60 ms) but the message sent takes 20wpm/10wpm=2 times longer due to longer letter and or wordspaces.

A different definition of effective speed may be that in standard text (paris paris...)there is 38% of the transmission occupied by letter and wordspacing, Effective speed becomes than 10 wpm
when you make the 38% spacing so much longer that the number words (paris) reduces from 20 to 10 per minute

I disagree with the validity of your measurement, because when you choose custom 5 charaters p a r i s, then an exercice does contain those characters random distributed, hence not the same number of P's A's R's I'and S's in your exercise.

Just apply the basics of probability theory.

Good luck



Posted: 2010-02-14 14:24
Digieet,

I am not the only one who has some doubts about the effective speed settings: In the User Forum (http://www.lcwo.net/?p=forum&t=252) there was a short discussion about this subject as well.

I'll invite you to measure the effective speed yourself.

Chris
[deleted]

Posted: 2010-02-14 15:47
Chris

I took your invitation.
The measurement setup was as follows:

= select in CWsetup custom characters PARIS only.
= tone 500 Hz fixed,
= exercise 1 minute
= speed 20 wpm effective 5wpm, because you noticed there the largest difference with your expected value.
= download via link to MP3 the MP3 to your own computer media player.

First of all : you said you have a fast computer and hence may be the letters come faster.
That is not true, when you play MP3 music the music will also not go any faster.

Secondly: The total playtime of that MP3 file is not worth to measure. That depends on the inter word (codegroup) spacings and that is in real time the time you are using to type the result of your decoding in the exercise window and during the exercise the MP3 is pausing, waiting for you pressing the ENTER key.

To check my measurementmethod I measured the duration of one sinewave. That was 2 ms, because the frequency is 500 Hz the time domain measurement conforms the pitch

I measured the dot 60 ms the dash 180 ms and the spaces in a letter between dots and dashes 60 ms.
The rise and fall time of the signal elements is somewhat more than 5 ms. That is to reduce key click. As I indicated before in this thread, the character speed in 20 wpm indeed (60 ms dit time)

And now the letter spacing, the letter spacing turns out to be 720 ms. That is 12 dits, that is 4 times the standard letterspacing of 3 dits.

Hence I think that DJ1YFK reasoned that the effective speed decreases a factor 4 (from 20 to 5wpm) when you increase the letterspacing by a factor 4.

Let we see what the effect is when you increase the letterspacings and the wordspacings on a message containing 20 words PARIS which should standard take 1 minute with a dit time of 60 ms.

PARIS is 31 dits letter and interletterspacins
and 19 dits letter and wordspacings. With a ditlength of 60 ms this fits exactly 20 times in one minute. 3 second per word.

Now however you make the letter and wordspacings 4 times longer, then the message takes 6,42 s per word and 128,4 s for the whole message.

Hence : I agree with your conclusion the effective speed becomes just below 10 wpm instead of the suggested 5. However that is an intuitive definition of effective speed. I measured also the sound 20wpm effective 5 wpm of the program of LB3KB That turns out to be a little bit more sloppy with dittime, but there ALSO is the dittime 60 ms (20 wpm) and the letterspacing 720 ms.




Posted: 2010-02-14 16:16
Thank you very much!

I came to the same conclusion by measuring the 20/10WPM mp3 example and found the spaces to be doubled, which resulted in 69 dots for paris instead of the expected 100dots or 600ms.
The doubling is done for both the letter and the word space.

So 10WPM double the space and 5 WPM quadruples it, but this is not enough to get desired speed.

Another inconvenience is the practice length setting. The transmission length is derived from time/(effective WPM) instead of the real time.

So if I use 20WPM with no additional spacing, and only use the 'e' character the practice session stops after 30s (5x'e' = 24 dots vs 50dots for 'paris') Only 20 groups were tranmitted, but 1min would allow for 40-41 to be send. There is no reason to stop the practice earlier.

The same is valid for the opposite case: If I select only '0' to be transmitted, then the practice length is 2:18 minutes. So if only 9 groups fit into a minute that's fine. It is not necessary to extend the length by that much.

I am looking forward to see these 'bugs' fixed.

I am really surprised to see only a few people realizing these issues. After all it is a great side, and the good news is:

You guys are faster than you think!

With this message, I wish everybody a nice Valentines Day or Carneval, whatever your preference.

Cheers,
Chris
[deleted]

Posted: 2010-02-14 17:02
Yes Chris

I just tested the program of G4FON.
His signals are even more discutable concerning leading and trailing edge than those of LB3KB, but he also has dittime 60 ms for 20 wpm (correct) But HIS letterspacings are in the 20wpm/5wpm mode 39 dits, his wordspacing is 64 dits.

I dont't think it is an important issue, just switch a low effective speed, independent of the meaning of that number, in order to reach your goal of copying all 41 characters at the speed of 20 wpm true paris speed.

I think, based on the measurement results mentioned above that the reasoning is as follows:
= You ought to hear the morse code of a character as one sound pattern.
= After hearing it as a complete pattern the decoding starts in your brain and has to be done before the next pattern is received.
= When you receive the pattern with 20 wpm speed (60 ms dit length) then you have the decoding time of a letter space (180 ms).
= By doubling the letter space to 360 ms you double the decoding time and makes it equal to the decoding time you have at the speed of 10 wpm.
= Hence the measurement of decoding difficulty in the case of doubling the letterspace, is equal to the decoding difficulty of 10 wpm with standard letter spacing.

Maybe that helps.


Posted: 2010-02-14 17:45
So overall the effective speed seems to be open to interpretation :-)

For learning CW this speed issue is irrelevant.

The good thing about this side, is that you do not need any special equipment and it is available where you've got the internet. So there is no excuse for not practicing anymore :-)
It also gives you excellent feedback about your progress.

After all you should not force it. Even when you don't have time, try to do at least a few minutes, and progress at your own speed.

I am really impressed that this side gained so much popularity in a rather short time. It will be interesting to follow Fabian next steps.

Chris


Posted: 2010-02-18 20:42
This is really a great subject for those of us who are re-learning the code over again. I hope this time it will be the right way: learning by sound pattern.(BUT at what speed) 20WPM charter speed and effective 10WPM word speed was to much for me to handle at the start. So I lowered the numbers untill I waS JUST A LITTLE UN COMFORTABLE .

now here is the question:should I re-do the lesson untill I can score a solid 90% at 20 and 10 ?
[deleted]

Posted: 2010-02-18 23:35
Yes , in my humble opinion you can start with K and M with a lower effective speed just as you did. But don't crank down the 20 wpm.

Then keep narrowing the gap by increasing the effective speed to at least 10 wpm before you go over to the next lesson. Same procedure there, in the next lesson.

Do not proceed to the next lesson before you meet the required low errorrate with at least 20/10eff.



Posted: 2010-02-19 15:08
I found that hitting the 90% score one time is not enough, I always continued until I achieved 90% at least three times before moving on. It took forever but I did complete the lessons.


Posted: 2010-02-19 22:51
Bill,

Congrats you did it!

My estimation is that when you exercise on a regular base every day 3 exercises it takes 800 exercises for 40 lessons. After that you can copy plain text with 20 wpm. That is an average speed on the amateur bands. You can write it down without problem and it is a nice speed to start copying by head without writing, just listening.

Doe this match your experience Bill?


Posted: 2010-02-19 23:07
I started thinking "what is the real starting speed that cwers should learn at and I came up with "the speed that they would really like to communicate at".After all everyone talks about how hard it is to break a plateau of difficulty at various speeds. After playing around with the 20/10 rule for morse code ,I found that I could hear the dit das at 40/10. Can you see where I am going with this line of reasoning ?

[deleted]

Posted: 2010-02-20 11:10
Sure I can Albert,

You think: "I should like to be able to copy 40 wpm as final goal."

Ludwig Koch who invented the method said that too:

"Start with the speed that you want to copy, because you learn the sound of that speed."

Certainly character h sounds dfferent at 40 or higher than at 20, more like a bundle of 4 playing cards that you release card by card when bended in your hands.

BUT I should say don't do it.

Of course you want to have some reasons why I turned down your bright idea:

1. The communication on the amateur bands is such that 90% is between 15 and 25 wpm. The added value of going above 25 is comparable to the added value addicts have from there second pint or gallon of alcoholic each day.

2. When you are able to communicate plain text at 20 wpm, you can make rag chew qso's at 20 and standard qso's or contesting around 35 and higher.
You can try this out here with Words and choosing "abbreviations". You easy recognise rst and qsl and my qth is.. Dont worry about the qth because usually it is sent twice and with larger character spacing.
Names are always short. Once I had a UA sending that his name was Ivanovitch, usually they are pretty soon tired of "pse rpt ur name" and use Ivan in the future. Or Bob. Bob is a good CW name, call yourself Bob and you never need to repeat that name. Digibeet is a bad one, so I use Bob on the bands.

3. It is not possible to copy the text of the course at 40 wpm on paper. It is very unlikely that your score is based on your ability to copy without at the same time testing your ability to type it in or write it down and after that type it over from paper in the window, for measuring your score.

4. When you touch type the code, you will not be able to join code proficiency test at hamfests and the like, where they usually require that you hand in your written text.

Handwriting, touchtyping and decoding in your head are three different proficiencies. Are you able to write 40 wpm? Try for one minute to write down paris paris ... I make it 35 times hence I will never be able to copy 40 with pen and paper.


An important thing in morsecode is that you can copy it just by listening without any decoders, and computers or other machines. Preserve that.


Posted: 2010-02-20 17:55
test (whoever you are)

It does indeed feel good to complete the 40 characters. You made me look up my practice results and I discovered that I have completed almost 800 lessons so far. That includes maybe 30-50 lessons after achieving a 90% score of all 40 characters. I practiced at 16/23. When done I could copy 20wpm plain text reasonably well. To be fair I learned the code well enough to pass the Extra exam (20 wpm) many years ago, but I forgot it all, I had to start all over.

This is clearly a wonderful site. Thanks to all who made it possible.

Sincerely,
Bill


Posted: 2010-02-20 19:19
Hello,
I do my cw training maybe in a personal way!! Arrived at lesson 15. Before doing my lesson at 25/10 I first start to listen several times to the letters at 35 . In order to get used to the higher speed. Then I change the speed down to 25/10 and doing my lessons. The result is that my average score increased very clearly.
greetings,
jack
[deleted]

Posted: 2010-02-20 21:43
That is a good advice Jack.

You are going pretty fast, just a month ago or so you presented yourself. Because you are already arrived at lesson 15 right now, I estimate you are doing at least 20 exercises each day.
Point is that you wil reach your goal 25 wpm in only 2 month. A stimulating idea for inpatient younger people.

Koch did not advice lengthened spaces between characters, (effective speed lower that character speed) What is your and Bill Walsh's experience with narrowing that gap?


Posted: 2010-02-21 01:46
To Digibeet:
I actually did a lot of experimenting with this program and then gave myself a lot of time to think of the "pit-falls" and problems with my statement of 40/10 to learn morse code over again.
the "pit-falls" was I knew that 40/10 was wronge from the start, since the site host (is that you ?)would not have told me to use 20/10 unless he knew that was correct.As it turned out ,I went with 35/5 and had good results at learning.
I remember reading about this Amatuer in the western USA who could read CW at about76 WPM and about the man who invented the Vibaplex and what a wonderful story it is.And he was an expert telegrapher. Well these people can only talk with the Mythical-gods of anchient,at those speeds, but I thought that if I aim for 40wpm I would surely copy at 20/25 wpm which is normal. (By the way,my first name is Al,one letter shorter than Bob,is Al better than Bob ?)
Problems:yea I know that I can barely write at 40wpm and have problems with touch-type since I do not know the key-board all that well.
then, I learned not to volenteer and never be a show-off because there is always -always someone better than you.
Then there is the reverse-plateau problem:after learning at 40wpm, do you have to learn all over again the code at 20wpm because it does not sound the same ?
Also, how do you make the transition of reading the code in your mind. Can this be done from the beginning ? Or at least practising it.
I see now that my biggest problem has always been that I was only able to learn half of the letters at INSTANT RECOGNITION .I am still on lesson 1 and 2 even though I have made some 100% runs.
Well,I guess that you would suggest that I go back to 20/10 even though I can not do that well.The letters come at me to quickly(at 20/10) and if I loose my place, my mind shuts down untill there is a space.I get "like rattled" is all that I can think of how it feels.
Should I stay with 35/5 ?
[deleted]

Posted: 2010-02-21 11:25
Al

Bob is what they call in linguistics a palindrome. That is a word that you can read backwards and find the same. Those special words are easier to copy. That is an interesting phenomena because it tells something about the working of the brain. QRQ is another one. Another example : 73
Hence I think Bob is possibly easier to copy than Al. You can make Al a palindrome by converting it to Alla, but I am afraid in that case you will get problems with fanatics.


There is one disadvantage with Bob, when you are sitting on a table in a canteen and your mates are eating bread or Mafiatorte and they call for your attention by calling your name with a mouth that is not empty, the B is the origin of raining wet pieces of their meal in your direction. In the canteen you are better of with Al, sure.

When you increase your speed above your abilities you wil find (I did) that copying words with longer palindrome characters such as o and m
are first recognised.

I am guest on this website. When you click with your mouse on my ID left of this message you can read my data.

You are registered on feb 18 on this website, hence I think you better try for at least a month or so the advised 20/10 or lower 20/5 when you have frustrating problems, before you are going at 35 or 40.

Jack DJ7PA presented a good advice: start listening the new characters high speed, and go then back to 20/5 asap 20/10 That prelistening will decrease your errorrate significant. At least in his recent experience.

I did also think about the reverse plateau, but I never met a guy that cannot copy a much lower speed. So, I don't know.

Normally when you start a series of 1 minute sessions slow, at 10 or even 5 wpm, morse is harder to take than at 20 wpm.
Furthermore, when you increase speed in one minute plain text sessions 10 15 20 25 30 etc, you copy easier than sessions of unexpected unknown random speed which is constant during one minute.

In my experience even a routine touch typist (touch typing is blind typing) falls back severely in speed by copying morse. You have to exercise everything you want to be able to do.

When you exercise 35/5 you have characterspacings of 0.72 s
When you exercise 20/10 your character spacings are 0.36 s
When you exercise 20/5 your character spacings are also 0.72 s
When I did not miscalculate, you can expect that 20/5 is better to start with and try narrowing te gap to 20/10 before you proceed to the next lesson.




Posted: 2010-02-21 13:13
Hi, Back to what I am doing. I experienced at about lesson 5 at 20/10 that I missed the word spacings. Then i tried to find out at what rate I heard the word spacing keeping the character speed at 20. The result was 20/8.
I didn't want to go to a less effective velocity because it is difficult to fight back.Therefore I advice not to be too drastically with your changes. Be careful with the treasure you acheived .The next trial will be at lesson 16 to go for 27/10 and find out what happens. For sure it first will be difficult because of the panic milliseconds between reading and writing. Hi.
73's
Jack


Posted: 2010-02-22 11:43
Al,
I beleif the topic is the total time you need to detect a character and write it down. Which means that if you need too much time to detect a character(due to a high character speed) the remaining time t to write it down is less.
With the result that you are tending for a lower
speed. I think that this is in your case the fact.
My experience is that at the moment ,at the end of a lesson, when the score is going up to above 85 or 90 %,i get the feeling i have enough time to write the characters down.
73's
jack


Posted: 2010-02-22 14:03
Jack,

You will not have more difficulties with copying
27/10 than you had with 20/10.

As far I understand the calculations made in this thread, your decoding time - that is the character spacing, is the same, and it is the spacing that is the same as with 10 wpm regular morse transmissions.

Hence the problem is nit to increse the 20 to 27 but to increase your number after the slash from 8 or 10 to 20.

I dont like the farnbourg sound'of the longer character spaces, it sounds very hacky, not the fluent sound that CW ought to make.


Posted: 2010-02-23 16:57
Test - Test user,
tnx or tu ??? I got your point. Tried 35/10 which functions by now way. Just listening to 35/10 I feel I can copy. So after the slash there is the bottleneck hi.!! Afterall the lessons work. Made my first dx's on 40. Listened into the contest of last weekend. Too many cw professionals!!!.
[deleted]

Posted: 2010-02-23 17:38
Hi Jack,

Don't be impressed. Those guys read

http://www.morsecode.nl/KH2DContesting.PDF

and apparently You did not.





Posted: 2010-02-23 18:49
Hi Digibeet-----I followed your advice of your 2010-2-21 thread (paragraph 4) and saw 2 characters with your name under my cusor. I had a little confusion on my part, but I figured you were the "BIG DOG" in the chair. Was I right ?


Posted: 2010-02-23 18:54
Yea, I finally figured who the site host was...
he is right under my nose.
[deleted]

Posted: 2010-02-23 20:03
Yep Albert I am the black one in the chair.

Black is beautiful, you dont have to get a shower even not when you have ur QRL in coal mining unless you are working in a wheat plant.

DJ1YFK is the designer and owner of this site.
Recently You don't read much from his hand. May be he is busy with his Masters thesis, and/or what man are used to be busy with in their early twenties.


Posted: 2010-02-26 12:43
Digibeet,
Indeed i didn't read. I wrote hi! Went from 25/10 up to
27/10 at lesson 16. It needs more concentration. Difficult character in 16 is the "=". The s is positioned outside the direct view on my keyboard,
73's

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