CW for beginners, lesson 1

The following is an explanation of sending the word "paris" in cw to help the beginner understand the sending cadence required to allow someone to decode it properly at the other end. The word "paris" is used as the standard for determining the speed of sending in words per minute (wpm) i.e. if you send the word "paris" 12 times in a minute, you are sending at 12 WPM.

Definitions:
1) Element : A length of time equivalent to the length of a "." (di or dit) in cw. The actual time used in sending a "." changes depending on words per minute being sent, so we just refer to this time duration as an element for this explanation.
2) Dah Symbol: ( _ ) equivalent to 3 time elements.
3) Di Symbol: ( . ) pronounced "di"(mid-letter) or "dit"(located at end of a letter), equivalent to 1 time element.
4) Symbol space : (') duration equivalent to 1 element.
5) Letter space : (,) duration equivalent to 3 elements.
6) Word space : (/) duration equivalent to 7 elements.

The word "paris" consists of the following letters (given with cw equivalents in symbols with time duration in elements):
P (. _ _ .) = 2 Di symbols (2 elements), 2 Dah symbols (6 elements).
A (. _) = 1 Di symbol (1 element), 1 Dah symbol (3 elements).
R (. _ .) = 2 Di symbols (2 element), 1 Dah symbol (3 elements).
I (. .) = 2 Di symbols (2 elements).
S (. . .) = 3 Di symbols (3 elements).

A total of 22 symbol elements, however we need to include symbol space elements:

P (.'_'_'.) = symbols (8 elements) + symbol spaces (3 elements).
A (.'_) = symbols (4 elements) + symbol space (1 element).
R (.'_'.) = symbols (5 elements) + symbol spaces (2 elements).
I (.'.) = symbols (2 elements) + symbol space (1 element).
S (.'.'.) = symbols (3 elements) + symbol spaces (2 elements).

A total of 31 time elements,however we must also include 4 letter spaces and 1 word space to complete the understanding that we are sending a 5 letter word:

P (.'_'_'.), = symbols (8 elements) + symbol spaces (3 elements) + letter space (3 elements).
A (.'_), = symbols (4 elements) + symbol space (1 element) + letter space (3 elements).
R (.'_'.), = symbols (5 elements) + symbol spaces (2 elements) + letter space (3 elements).
I (.'.), = symbols (2 elements) + symbol space (1 element) + letter space (3 elements).
S (.'.'.)/ = symbols (3 elements) + symbol spaces (2 elements) + word space (7 elements).

A total of exactly 50 time elements. So to send the word "paris" takes exactly 50 time elements. 

Example: To define the time duration of 1 element when sending at 12WPM:
12 words x 50 elements = 60,000 ms.
element = 60,000ms/600 elements
element = 100ms.

The purpose of this exercise is that now you will understand why sending cadence is everything when sending cw successfully. You will also now appreciate that a computer will send perfect cw whereas a human will send cw with imperfections. This is why the majority of serious cw contesters use the computer to send cw 90% of the time.

Doug (GM0ELP)