3. The aircraft should be maneuvered into a
favorable position so that the signaler can have an
unobstructed view for as long a period as possible.
4. Accurate training of the light by the operator at
all times is most important.
Aircraft are called by the means of the prosign AA,
the unknown station. Many aircraft cannot signal by
flashing light, and an answer should not always be
expected. If no answer is seen, the message is to be
made through at least twice; repetitions are to be
preceded by the prosign IMI. Receipt may be indicated
by the aircraft rocking its wings.
Infrared communications are divided into two
forms: directional and non-directional. Directional is
the use of the standard searchlight fitted with the H
hood. Nondirectional is the use of the AN/SAT 2
system located on the yardarm.
Infrared communication between separate ships is
generally directional. A station having traffic for wide
distribution will normally use non-directional
The OTC may prescribe calling periods during
which infrared traffic may be passed without a special
signal to attract attention. For example, stations may
be required to monitor for infrared signaling for 15
minutes beginning on the hour and half hour. Such
instruction may be found in the operation orders,
communications plan, or message traffic calling
periods. At the beginning of the calling period, the
OTC may transmit the appropriate operating signal
and the call signs of the stations the traffic is for.
Stations not included in the traffic list may secure their
equipment unless they have traffic for the OTC or
other units in company.
To transmit infrared traffic outside calling periods
or when calling periods have not been prescribed, the
stations may be alerted by the code word NANCY
HANKS on voice radio, the appropriate signal from
ATP 1, volume II, or an operating signal.
The point of train (POT) light is a steady
infrared light used to assist the sender in locating the
receiving station and in keeping his/her light properly
trained. It is turned on to indicate that a station is
communicating or is ready to communicate with
infrared. It is turned off at all other times. In the event
of non-directional procedure, the originator's POT
lights will become its Nancy beacons, and the
receiving stations will be able to train their receivers
on the actual transmission.
LEARNING OBJECTIVES: Explain the
procedure for calling, receipting, and
requesting repetitions, interruptions, and relays
by semaphore. Explain procedure for
transmitting, rate of signaling, and the use of
numerals. List special characters and
Semaphore and flashing light can be used
interchangeably. Semaphore is much faster and
generally more secure than flashing light for
short-distance transmission in clear daylight.
Semaphore may be used to transmit messages to
several addressees at once if the sender is in a suitable
position. Because of its speed, it is better adapted for
long messages than other visual methods. Semaphore
can be used at night with the use of wands attached to
flashlights. See appendix II for semaphore drills and
Semaphore signaling procedures are similar to
those used in flashing light. The general rules of visual
responsibility apply; call signs are the same; and
message parts are unchanged. Because of the different
equipment used, some differences in procedure do
Care is to be exercised in selecting a good
background from which to send a semaphore message.
The better the background, the greater the signaling
The characters are to be formed in the same plane
as the sender's shoulders, with staffs at their full
extent, forefingers along the staff. When the sender is
making the front sign, the flags should be crossed in
front of the body.
A distinct pause is to be made at each character
according to the rate of signaling. When
transmitting prosigns, operating signals, and
abbreviations, make this pause of double duration.
A double-duration pause is also recommended when
sending coded messages.
The front sign is made at the end of each word,
group, prosign, or operating signal. Where double
letters occur, the arms are to be dropped to the front