TC 9-64 _________________________________________________________________________
LEARNING OBJECTIVES
4-2.
Upon completing this chapter, you should be able to do the following:
State the basic principles of antenna radiation and list the parts of an
Explain current and voltage distribution on an antenna.
Describe how electromagnetic energy is radiated from an antenna.
Explain polarization, gain, and radiation resistance characteristics of
an antenna.
Describe the theory of operation of half-wave and quarter-wave
antennas.
List the various array antennas.
Describe the directional array antennas presented and explain the
basic operation of each.
Identify various special antennas presented, such as long-wire, V,
rhombic, turnstile, ground-plane, and corner-reflector; describe the
operation of each.
List safety precautions when working aloft and around antennas.
RADIO FREQUENCY SAFETY PRECAUTIONS
4-3. Although electromagnetic radiation from transmission lines and
antennas is usually of insufficient strength to electrocute personnel, it can
lead to other accidents and compound injuries. Voltages may be induced in
ungrounded metal objects, such as wire guys, wire cable (hawser), handrails,
or ladders. If you come in contact with these objects, you could receive a shock
or radio frequency (RF) burn. This shock can cause you to jump or fall into
nearby mechanical equipment or, when working aloft, to fall from an elevated
work area. Take care to ensure that all transmission lines or antennas are
deenergized before working near or on them.
4-4. Either check or have someone check all guys, cables, rails, and ladders
around your work area for RF shock dangers. Use working aloft "chits" and
safety harnesses for your own safety. Signing a "working aloft chit" signifies
that all equipment is in a nonradiating status. The person who signs the chit
should ensure that no RF danger exists in areas where you or other personnel
will be working.
4-5. Nearby ships, vans or parked aircraft are another source of RF energy
that you must consider when you check a work area for safety. Combustible
materials can be ignited and cause severe fires from arcs or heat generated
by RF energy. Also, RF radiation can detonate ordnance devices by inducing
currents in the internal wiring of the devices or in the external test
equipment or leads connected to them.
4-6. Always obey RF radiation warning signs and keep a safe distance from
are shown in figure 4-2.
4-2
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