LESSON ONE
TRANSMISSION LINES
TASK
Identify transmission lines used with radar systems, describe the
composition and electrical characteristics of real transmission lines on
schematic diagrams, and determine time delays in artificial transmission
lines.
CONDITIONS
(Performance-Oriented) Given this subcourse, pencil, and paper.
STANDARD
(Performance-Oriented) Demonstrate competency of task skills and knowledge
by correctly responding to 75 percent of the multiple-choice test covering
radar transmitters.
REFERENCES
FM 11-63
Learning Event 1:
RF TRANSMISSION LINES
1.
GENERAL.
a. RF transmission lines are used to transfer or guide RF energy from
one place to another with a minimum loss of power. Transmission lines serve
as the connecting link between a source of power and the load which uses the
power. Transmission lines in radio, television, and radar systems guide the
RF signal from the transmitter to the transmitting antenna and from the
receiving antenna to the receiver.
b. RF transmission lines are like the wires that carry electric power
and telephone messages to your home.
In fact, all transmission lines
contain
the
same
basic
properties of
inductance, and
In this respect a transmission line is similar to ordinary
circuits. However, the basic low-frequency transmission line made of wires
is not an efficient carrier of RF energy because power losses increase as
the operating frequency increases. RF transmission lines therefore, must be
carefully designed to overcome the limitations of the basic low-frequency
line. Regardless of the operating frequency, all transmission lines should
have the smallest possible losses in order to transfer the maximum power to
the load.
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