CHAPTER 1
COMMUNICATIONS
As an Aviation Electronics Technician, you will be
tasked to operate and maintain many different types of
airborne communications equipment. These systems
may differ in some respects, but they are similar in many
ways. As an example, there are various models of AM
radios, yet they all serve the same function and operate
on the same basic principles. It is beyond the scope of
this manual to discuss each and every model of
communication equipment used on naval aircraft;
therefore, only representative systems will be discussed.
Every effort has been made to use not only systems that
are common to many of the different platforms, but also
have not been used in the other training manuals. It is
the intent of this manual to have systems from each and
every type of aircraft in use today.
RADIO COMMUNICATIONS
Learning Objective: Recognize the various
types of radio communications. Identify the
various frequency bands and their uses and
limitations.
In basic terms, communication is defined as the
meaningful transfer of information from one location
(the sender, source, originator) to another location (the
destination or receiver). Electronic communication uses
electrical energy to transmit the information to be
communicated Since this electrical energy travels at the
speed of light, the transfer can occur within a fraction of
a second. The information must be converted from its
original form of sound, light, or mechanical energy into
electrical energy. This electrical energy can then be
transmitted via wires or radiated through space to a
receiver. The receiver must then convert the electrical
energy back into its original form to complete the
communication cycle.
TYPES OF RADIO COMMUNICATIONS
Radio communications has become a highly
sophisticated field of electronics. All Navy aircraft have
the capability to use the commonly used ship-to-ship,
ship-to-air, air-to-air, air-to-ground, and ship-to-shore
communication circuits. These operations are accom-
plished through the use of compatible and flexible
communication systems.
Radio is the most important means of com-
municating in the Navy today. There are many methods
of transmitting in use throughout the world. This manual
will discuss three types. They are radiotelegraph,
radiotelephone, and teletypewriter.
Radiotelegraph
Radiotelegraph is commonly called CW (con-
tinuous wave) telegraphy. Telegraphy is accomplished
by opening and closing a switch to separate a
continuously transmitted wave. The resulting “dots” and
“dashes” are based on the Morse code. The major
disadvantage of this type of communication is the
relatively slow speed and the need for experienced
operators at both ends.
Radiotelephone
Radiotelephone is one of the most useful military
communication methods. It is used by aircraft, ships,
and shore stations because of its directness, con-
venience, and ease of use. The equipment used for
tactical purposes usually operate on frequencies that are
high enough to have line-of-sight characteristics. This
cuts down not only on the possibility of the enemy
intercepting the messages, but also cuts down on the
distance between the transmitter and receiver.
Teletypewriter
Teletypewriter (TTY) signals may be transmitted by
either landlines (wire), cable, or radio. The Navy uses
radio teletypewriter (RTTY) for high-speed automatic
communications. The keyboard used with a TTY system
is similar to that of a typewriter. When the operator
strikes a key, a sequence of signals is transmitted. At the
receiving station, the signals are translated back into
letters, figures, and symbols that are typed onto paper
for use.
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