May, 1997

If you can turn something on and off  (a carrier, a light, a car horn, a 
bell), or interrupt something  (light from a distant lamp, the sun, a star, 
smoke from a fire, the power to a city block) - or wave something (a flag, 
your arms, your ears or eyelids) - then you can communicate IF YOU KNOW 
MORSE!  For manual Morse IS THE LEAST TECHNOLOGICALLY COMPLEX WAY OF 
MODULATING A SIGNAL SOURCE!

A radio transmitter has various sections inside it.  The first, without 
which the transmitter would be useless, is the carrier oscillator.  This 
circuit generates a radio frequency voltage - a sine wave of constant 
frequency and amplitude, called a continuous wave.  Everything else 
the transmitter does uses this carrier.  It amplifies it, modulates it, 
shifts its frequency, and then puts the result on the transmitter's 
antenna jack.

The simplest thing a transmitter can do to this carrier is to turn 
it on and off.  By providing another jack where you, the operator, can 
connect a switch, the transmitter lets you turn the carrier on and off 
conveniently.  The switch is known as a telegraph key, and the 
operating mode where you turn the transmitter on and off to communcate
is called CW, an abbreviation for continuous wave, even though 
the output is not continuous!



THE STRUCTURE OF MORSE CODE - FROM AN ENGINEER'S VIEWPOINT.


Timing of "dits" and the letter space


Morse sends information by turning a transmitter on and off in a well- 
defined pattern.  Suppose you connect a key to your transmitter, and sit 
by it with a watch on your left wrist.  The watch has a "seconds" display. 
You start at 15 seconds past the minute and wait . . wait . . until 
exactly 30 seconds past.  At that time you press the key down for 1/2 
second, let it up for 1/2 second, and do this four more times. We 
engineers describe this action like this:





The graph we draw depicts time in seconds passing away along the 
horizontal axis, from left to right - our time axis always goes from 
left (the past) to right (the future). The vertical axis shows whether 
the transmitter is "on" - key "down" - or "off" - key "up".

Notice that this string of five dits, which ordinary people call 
"dots," consist of alternating one-half second intervals when the key is 
down with intervals when it is up. This pattern, in morse, is brought 
to you by the number five. It is the number five, when properly 
sent by a cw (aka Morse) operator.

There's a very important part of the number five, and all other letters, 
numbers, or symbols you can send by CW.  At the end, the key must 
be "up" for two more time intervals!  This is called the "letter 
space" and is used to separate one letter, number, or symbol from another.
Thus 5 starts at the first dit, and lasts until the "stop" mark 
shown on the graph.

Morse uses patterns of on/off based on a single time unit - the dit space. 
A dit - please, not a dot! - takes two dit space intervals, 
and a dahhhhh (I drag it out to show that it lasts longer than a dit) takes 
four dit spaces.  The dit has a key down time of one dit space, and the 
dah has a key down time of three dit spaces - three times as long as a dit. 

When you add the single dit space of key up at the end of a dit and a dah, 
you find that a dit takes two dit spaces, and the dah takes four.  
Basic timing, then, puts two dits in the space on one dah - when the dah is 
three times as long as the dit.  The ratio of dah length to dit length is 
called weighting.  For now, keep your practice on this standard 
3:1 weighting.  Remember this - it will be important in the exercise 
section later.
 
This graph depicts the timing of the dit and dahh.



Now consider IT - the word, that is. This graph shows how IT 
appears with key up/key down patterns.





The "I" is  "di dit" - two fast dits that, when you speak them, slur 
together, losing the "t" on all but the last dit. The "T" of "IT" is a single
dah.  Notice the letter space between the  I  and  T  in the graph. Without it, 
the dits and dah will run together, making something not intelligible as 
"IT."  The letter spaces are shown in bolder line width here only to 
emphasize that they are necessary parts of good Morse!

Also notice that the end of a word has two letter spaces, which separate 
the word from the next word.  This is called a word space. Thus Morse 
has four basic elements:


the dit - two dit spaces long
the dah - four dit spaces long
the letter space - two dit spaces long
the word space - four dit spaces long.

You have heard, or will shortly hear, about CW operator's "code speed."
This is stated in words per minute, or WPM. Before the FCC changed
the rules in April of 2000, getting a Novice license required your code speed 
to be 5 WPM; a general, 13 WPM; and an extra, 20 WPM.  So what is a word?  
U.S. Army Signal Corps standards in the fifties used "PARIS" as the length 
of a standard word.  My code training equipment back then used paper tape 
keying machines, and each tape had a long leader of repeating "PARIS" so I 
could count the repetitions to set machine code speed.  Here is a graph of PARIS:





It starts at the "Start" mark.  P has the pattern  di dah dah dit. Look 
closely at the graph.  Notice the structure of the dits and dahs, and 
the letter space after the last dit. A small arrow marks the end of  P
and the start of  A.  Follow the graph to see the structure of 

P - di dah dah dit
A - di dah
R - di dah dit
I - di dit
S - di di dit
  - the letter spaces
  - the final two letter spaces, or word space

PARIS - the standard word - takes 48 dit spaces of time.

Since a "word" takes 48 dit spaces, a speed of 5 WPM will have 240 dit 
spaces per minute. A single dit takes two dit spaces, so a continuous 
string of dits, at 120 per minute, is code being sent at 5 WPM.  My very 
first graph above shows five dits at one-second intervals - this is a code 
speed of 2 1/2 WPM.

Code speed then has:

 
120 dits/minute,  60 dahs/minute -  5 WPM
312 dits/minute, 156 dahs/minute - 13 WPM
480 dits/minute, 240 dahs/minute - 20 WPM

CW operators each have individual "sounds" to their rhythmic tapping of 
the key - or, as we say, pounding the brass. Some are beautiful 
to hear. Others need some practice. Still others are almost intelligible. 

To be complimented on one's fist - the beautiful, rhythmic pattern 
produced at brass pounding - is indeed a lofty goal. To be found out 
as a lid - a poor operator - is cause for concern and need of 
improvement. Ham radio, unlike the internet, does not engage in flame
wars. Instead, we hams try our best to help one another, and take pride 
in doing so. That's one reason I have written this. 


          Step 1 - position

Establish a comfortable position.  Sit in a chair facing 
your operating table. Place the key on the table about even with your 
left shoulder. It should be fastened to a thin base, or to the table 
itself.

Put your right elbow on the table. Bend your right arm so your right hand 
touches the key. Move the key to do this: your thumb, index finger, and 
middle finger should all be able to touch the key's knob.

Put your index finger on top of the knob, and use your thumb and middle 
finger to very lightly squeeze the opposite sides of the knob. 
Don't overdo the squeezing - you should just be able to lift the key up 
with the right finger positions.  Let your ring and little finger curl up 
lightly under your hand.  You've now made a very loose fist.

Put the fingers of your left hand under your right wrist.  Relax.

Now lift your right wrist just a bit and let your hand fall limp: your 
index finger should then fall heavily enough on the knob to just about 
close the key.  A very slight downward pressure with your hand will 
complete key closure.  Do not "push forward" with your arm to close 
the key: get the feel of hinging your hand at the wrist, with the forearm 
not moving.


          Step 2 - adjusting the key

Adjust the gap under the key contact.  Open the gap with the rear screw 
on the key.  Adjust the side screws so the armature - the part that rocks 
up and down - doesn't wobble from side to side.  Also adjust them so the 
armature contact is centered over the base contact - these are usually 
just ahead of the front screw, on the bottom side of the armature.  Don't 
overtighten the side screws.
  
Then adjust the rear screw for clearance, using a sheet of paper, 
or sometimes an ace of spades.  Tighten the gap until the card or paper 
can just be pulled out easily.  Do not overtighten.

When this is right, raising your wrist should let your fingers fall on the 
key knob and close the contact.  Adjust the key spring tension - the front 
screw - to get the right tension.  Too heavy a spring will demand that you 
move your forearm, and this will cramp your "wrist" in a short time.


          Step 3 - getting the beat

Find a metronome or get some other way to produce 120 audible beats per
minute. I coudn't afford a metronome, so I practiced in our kitchen. I 
let the faucet drip onto the back of a pan, and adjusted it for the beat 
rate I needed.

Listen to the beat. Practice pressing the key down on one beat, and 
releasing it on the next. Keep this up for at least one minute. If your 
arm or wrist begins feeling cramped, you are not relaxing enough.
This is not physical exercise - it is an exercise in relaxing and getting 
the feel of an even  on - off  action of the key.


          Step 4 - dits and dahs

With the metronome going at 120 beats per minute, press the key for one 
beat. Release it on the 2nd beat. Press it on the third beat. Release it on
the fourth beat. Press and hold it on beats 5, 6, and 7.  Release 
it on beat 8. Keep repeating this pattern seven more times.  Notice that 
this exercise demonstrates the 2:1 ratio between dit timing (2 dit spaces) 
and dah timing (4 dit spaces.)  2 dits = 1 dah.

You have now practiced the proper timing of sending " di di dah" eight 
times. After you feel comfortable with this, increase the metronome speed 
to 160 beats per minute, and repeat this pattern. Increase metronome speed 
to 200 beats per minute, and repeat the pattern again.


          Step 5 - rhythm practice patterns

After you get the hang of step 3, try all other patterns:

di di dah - - 8 times
di di di di dah dah - - 8 times
di di dah di di dah di di di di dah dah - - 6 times
dah dah di di - - 8 times

Do these at speeds up to 200 beats per minute. Practice often.


          Step 6 - double time

Set your metronome to 120 beats per minute. Do the same patterns as above, 
but key one dit and its following dit space per beat: you will be 
keying at twice the rate as before: a "di di dah" pattern will be completed 
in four metronome beats, not eight.

Here is a common pitfall. Pay close attention to your dahs. It is 
a common mistake to make them two dit spaces long, followed by a 
gap of two dit spaces.  This will mark you as a lid!  Your dahs must be 
syncopated - that is, you must count the metronome beats
as musicians do: "one and two and three and four 
and one and two, etc." The dah of "di di dah" starts on 
"three" and lasts throughout  "three and four," you release 
pressure on the "and" following "four."

These rhythm drills, if practiced regularly for a few months, will improve 
your "fist" as heard by other amateurs. The result will be worth the toil.



BUGS AND KEYERS


The beginner should not know what these devices are.  If he does, he should 
not try to use these devices for at least 18 months after starting on 
a straight key.  I was told by my mentors that trying to adapt to a "bug" 
too soon would ruin your fist!

A keyer is an electronic device connected to two vertical paddles.  
Your thumb operates the left paddle, and your index finger the right paddle. 
The thumb presses its paddle, and the electronics begins sending "dits" one
after another.  The finger presses its paddle, and the electronics sends 
"dahs" one after another.  Pressing both paddles can cause alternating "dits" 
and "dahs" - called iambic mode.

A "bug" is a similar, mechanical device that sends "dits" when the thumb 
paddle is pressed, and sends "dahhs" manually by alternating pressing 
and releasing the finger paddle.  Experienced CW operators will often send 
manual morse with the dah paddle alone, using it as a hand pump on its side!

There are variations on keyers and bugs.  I have seen a bug with two
actions - one sends dits as usual, and the other sends dahs.  It takes a bit 
of care to get the two weighted actions adjusted correctly for this!

Again - you are cautioned against trying these devices too soon! Spend 
at least a year and a half on a straight key, and get your code speed up to 
about 15 wpm or better, before trying keyers or bugs.




73

K3MT