minute, an experienced SM probably will reply at the
same rate; but you will be out of luck if you can read
only 6 or 7 words a minute. Speed, incidentally, does
not imply noise. The shutters can be moved quickly
without banging them up and down.
When you are first learning to send code by light,
it is wise to increase the interval between characters
and groups. The extra time enables the beginner to see
each character in the proper time ratio. Moreover, the
greater period between the characters and groups
allows the mind to verify or realize what the eyes have
seen. Practice reduces this reception time, and the
periods can be decreased.
The period the shutter remains open for a dit or dah
and closed between characters and groups, when sending
by flashing light, is given in the following list. Note that
the interval between dits and dahs is the same.
A dit equals 1 unit of duration.
A dah equals 3 units.
The period between dits or dahs in the same
character equals 1 unit.
The period between two characters equals 3 units.
The period between groups equals 7 units.
FLASHING LIGHT QUALIFICATIONS
Certain flashing light standards are required of the
Signalman for advancement to the third and second
class levels. You must demonstrate your ability to
meet these standards before you are recommended for
advancement. They are required as part of your
performance tests, which must be taken for
advancement in rating.
For advancement to Signalman 3, you must be
able to transmit and receive code groups at six groups
per minute, and plain language messages at an
approximate speed of eight words per minute. (Five
characters equals one group.)
For advancement to Signalman 2, you must be able
to transmit and receive code groups at an approximate
speed of eight groups per minute and plain language at
an approximate speed of 10 words per minute.
Following is a series of Morse code drills. Practice
each drill until you can send and receive it at the rate of
25 characters per minute before going on to the next
exercise. To estimate the time required to attain that
speed, divide the number of characters in each drill by
25. Drill 1, for example, contains 150 characters. Before
going on to drill 2, practice drill 1 until you can send or
receive it in 6 minutes.
B P 8 2 7 MGSDW
P S 8 5 P EB3WJ
6 B 8 2 H
F N L 0 8
8 7 H J 2 GKY3W
6 L S 2 G
J 2 8 N 6
C 0 5 3 6