U.S. Marine Corps Antenna Mcrp 6 22D Operating Instructions

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MCRP 6-22D
advantage based on polarization will be determined by the polariza-
tion of possible sources of interference. In deciduous forests the
sources are evenly divided between vertical and horizontal. In
mature coniferous forests the sources are predominately vertical, so
horizontal polarization has an advantage.
Power and Signal Lines
Distribute power and signal lines to eliminate and avoid crossovers.
If power and signal lines must cross, arrange them so that they cross
at right angles, and separate them by 4 feet of elevation. Do not run
power and signal lines parallel to each other.
ANTENNA FARM LAYOUT PRINCIPLES
• Segregate HF, VHF, and UHF channels.
• Maintain separation between antennas.
• Separate power and signal lines. Keep them out of the main
ground phase of antennas.
• Keep transmitters close to the feed point of their antennas (i.e.,
keep them short).
• Establish good RF and safety grounds for each antenna.
• Use ground radials for each antenna.
• Site LOS antennas on the highest ground.
• Site antennas to avoid the main lobes and significant side lobes
of directional antennas.
• Remote antenna farms 1 kilometer from the CP if practical. 
						

							Appendix A
GLOSSARY
Section I
Acronyms and Abbreviations
AM..............................................................amplitude modulationn
C.......................................................................................centigrade
CIS..................................communications and information systems
cm....................................................................................centimeter
COMSEC.................................................communications security
CP..............................................................................command post
dB..........................................................................................decibel
dBi..............................................decibels over an isotropic radiator
e.g..................................................................................for example
EW.......................................................................electronic warfare
FM.................................................................frequency modulation
FMFM...................................................Fleet Marine Force manual
FMFRP............................Fleet Marine Force reference publication
GHz...................................................................................gigahertz
HF.............................................................................high frequency
i.e.............................................................................................that is 
						

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kHz.....................................................................................kilohertz
km.....................................................................................kilometer
kW........................................................................................kilowatt
LOS................................................................................line of sight
LUF............................................................lowest usable frequency
MAGTF..............................................Marine air-ground task force
MCDP......................................Marine Corps doctrinal publication
MCRP......................................Marine Corps reference publication
MCWP.................................Marine Corps warfighting publication
MHz.................................................................................megahertz
mi.....................................................................................mile/miles
MUF.....................................................maximum usable frequency
NVIS............................................near-vertical incidence sky wave
RF...........................................................................radio frequency
SATCOM..................................................satellite communications
SCR..................................................................single-channel radio
SID.................................................sudden ionospheric disturbance
SINCGARS.........single-channel ground and airborne radio system
S/N............................................................................signal-to-noise
SPEED..........system planning, engineering, and evaluation device
SWR..................................................................standing wave ratio
TV.....................................................................................television
UHF..................................................................ultrahigh frequency 
						

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VHF..................................................................very high frequency
VHF-LOS.....................................very high frequency line of sight
VSWR..................................................voltage standing-wave ratio
W...............................................................................................watt 
						

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MCRP 6-22D
Section II
Definitions
A
alternating current—Current that is continually changing in mag-
nitude and periodically in direction from a zero reference level.
Also called AC.
amplification—The process of increasing the strength (current,
voltage, or power) of a signal.
amplitude—The level of an audio or other signal in voltage or cur-
rent. The magnitude of variation in a changing quantity from its
zero value.
amplitude modulation—Modulation in which the amplitude of the
carrier wave is varied above and below its normal value in accor-
dance with the intelligence of the signal being transmitted. Also
called AM.
angle of incidence—The acute angle (smaller angle) at which a
wave of energy strikes an object or penetrates a layer of the atmo-
sphere or ionosphere.
antenna—A device used to radiate or receive electromagnetic
energy (generally RF).
antenna bandwidth—The frequency range over which a given
antenna will accept signals.
antenna feed—Means by which power is transferred to and from
the antenna and the connecting transmission line. 
						

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A-5
antenna gain—The effectiveness of a directional antenna as com-
pared to a standard nondirection antenna. It is usually expressed as
the ratio in decibels of standard antenna input power to directional
antenna input power that will produce the same field strength in the
desired direction. For a receiving antenna, the ratio of signal power
values produced at the receiver input terminals is used. The more
directional an antenna is, the higher is its gain.
array—Several simple antennas, usually dipoles, used together to
control the direction in which most of the antenna’s power is radi-
ated.
attenuation—Power loss resulting from conductor resistance and
dielectric loss within the insulating material used to separate the
conductors.
azimuth—An angle measured in a horizontal plane from a known
reference point.
B
balanced antenna—An antenna is balanced with respect to ground
when both its arms have the same electrical relationship to ground.
balanced transmission line—A transmission line whose conduc-
tors have voltages of opposite polarity and equal magnitude with
respect to the Earth.
balun—A device for feeding a balanced load with an unbalanced
line, or vice versa.
bandwidth—The width of a band of frequencies used for a particu-
lar purpose. 
						

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baud—The number of times per second the carrier signal changes
value.
bidirectional—In two directions, usually opposite.
blob—Small areas of the atmosphere where temperatures and pres-
sure differences produce conditions suitable for the refraction of
radio waves.
broadband antenna—An antenna capable of operation over a
wide band of frequencies
C
cable connectors—Fittings for cable ends which permit rapid con-
nection and disconnection with equipment or other cables.
capacitance—A natural property of an electrical circuit which
opposes the rate of change of voltage.
capacitor—A device for storing electrical charge.
center-fed—Transmission line connection at the electrical center of
an antenna radiator.
coaxial cable—A transmission line consisting of two conductors,
one inside the other, and separated by insulating material. The inner
conductor may be a small copper tube or wire; the outer conductor
may be metallic tubing or braid. Radiation loss from this type of
line is very little.
command post—The headquarters of a unit or subunit where the
commander and staff perform their functions. 
						

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communications circuit—The means by which information is
transferred between two or more places.
conductor—A material (usually metal) that has low resistance to
the flow of electrical current. A wire, cable, or other object capable
of carrying electric current. Good conductors are made of metals
such as silver, copper, and aluminum.
connections—Points at which two or more conductors are brought
into contact.
counterpoise—A conductor or system of conductors used as a sub-
stitute for ground in an antenna system; a wire or group of wires
mounted close to the ground, but insulated from ground, to form a
low-impedance, high-capacitance path to ground.
critical frequency—The highest frequency at which a signal may
be transmitted directly overhead and be reflected back to Earth
from the ionosphere.
cross-polarized—The polarization of a received signal is 90
degrees to the polarization of the receiving antenna.
current—The flow of electrons along any path.
D
decibel—The standard unit used to express transmission gain or
loss and relative power levels. Also called dB.
deflection—The displacement of an electron beam from its line of
sight path.
demodulate—To recover the information originally impressed on
the radio wave. 
						

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dielectric—A material that does not conduct electricity, such as
rubber or glass, i.e. an insulator.
diffraction—The process by which electromagnetic waves are bent
so that they appear behind an obstruction.
dipole antenna—A center-fed wire antenna whose conductors are
in a straight line.
directional antenna—An antenna designed to transmit and receive
RF energy in a specific direction(s).
direct waves—Waves which propagate in a straight line from the
transmitting to the receiving antennas.
directivity—The property of radiating more energy in some direc-
tions than in others.
director—A conductor placed in front of a driven element to cause
directivity.
ducting—The propagation of VHF/UHF wave by bouncing
between the Earth’s surface and the interface between layers of air
having different dielectric constants.
E
efficiency—The ratio of power output to power input.
electromagnetic field—The field of force that an electrical current
produces around the conductor through which it flows.
electromagnetic waves—A wave propagating as a periodic distur-
bance of the electric and magnetic fields and having a frequency in 
						

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the electromagnetic spectrum; the means by which energy is trans-
mitted from one place to another.
end-fed—An antenna whose power is applied to one end rather
than at some point between the ends.
F
fading— A periodic decrease in received signal strength.
feedpoint impedance—Impedance that is measured at the input
terminals of an electrical device such as an antenna.
fields—Regions in which each point has a value of a physical quan-
tity (voltage, magnetic force, velocity, mass, etc.).
free space—The absence of ground.
frequency—The rate at which a process repeats itself. In radio
communications, frequency is expressed in cycles per second.
frequency hopping—A method of jumping from frequency to fre-
quency in synchronization with one another in a random order at a
rate of up to 100 times per second. Frequency hopping is the pre-
ferred method of communication with SINCGARS radios. 
frequency modulation—The process of varying the frequency of a
carrier wave, usually with an audio frequency, in order to convey
intelligence. Also called FM.
frequency of optimum transmission—85 percent of the maximum
usable frequency (MUF). A practical frequency selection which
allows for MUF variations.