CHAPTER 1
FUNDAMENTALS
INTRODUCTION
Communications in general, and especially in systems, covers a broad spectrum, from a simple single-
channel voice circuit, to the fastest growing field of electronics—satellite communications. This training
manual will provide you with knowledge applicable to questions and situations that arise on the job. Chapter
1 is a refresher course in basic communications systems and terminology. Chapters 2 and 3 will lead you
through many of the systems and equipments in use today. Chapter 4 will discuss the Link-11 system, chapter
5 will cover the Link-11 Fault Isolation, chapter 6 will discuss Link 4-A, chapter 7 will introduce you to the
new technology in data communications and the Link-16 system, and chapter 8 will discuss local-area
networks.
The Electronics Technician rating is extremely diverse. Many ETs never get the opportunity to work in
the communications field. Those who do are often locked into one particular system for many years. This
assignment pattern sometimes causes ETs to feel overwhelmed or lost in their career. The massive amount of
information ETs can be questioned on and expected to know can be frustrating. But the goal YOU and every
ET must have is to become as knowledgeable as possible to be better. prepared for all future challenges.
After completing this chapter, you should be able to:
Identify the basic principles of rf communications
Recognize the basic equipment used for rf communications
Determine the frequency spectrum allocated to rf communications
RADIO COMMUNICATIONS
Navy ships, planes, and shore bases operate as a
team working together to accomplish a specific task.
Radio equipment is used to coordinate the activities of
the many fleet units by linking them with each other
and with shore stations.
Radio can be defined as the transmission and re-
ception of electronic impulses or signals through space
by means of electromagnetic waves. Usually, the term
is used in referring to the transmission of intelligence
code and sound signals, although television and radar
also depend on electromagnetic waves.
At one time, the term radio communications
brought to mind telegraphy (CW), voice (AM), and
possibly teletype communications. Today’s radio com-
munications has become a highly sophisticated field of
electronics. You, the technician, need to become fa-
miliar with the diverse systems in use today.
The primary means of communicating between
ships and between ships and stations is known as tele-
communications. Telecommunications refers to com-
munications over a distance and includes any
transmission, emission, or reception of signals,
writing, images, and sounds. Intelligence produced by
visual or oral means or by wire, radio, or other electro-
magnetic systems is also included. Electrical, visual,
and sound telecommunications are all used by the
Navy. In this volume we will discuss electrical types of
telecommunications.
COMMUNICATIONS SYSTEMS
A communications system consists of two or more
units, each having its own separate identity, arranged
and interconnected to perform a circuit operation that
cannot be performed by one of the individual units
alone. Navy communications systems vary from sim-
ple to very complex, depending upon the circuit opera-
tions involved. Each system requires the integrated use
of various types of equipment, so flexibility is of the ut-
most importance. This flexibility is provided through a
complex arrangement of interconnections that allow
the physically separated sets, groups, and units to be
selectively switched (patched) into the different circuit
configurations.
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