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

Antenna Handbook ____________________________ 
4-15
maximum gain at high take-off angles. In format D, the radiation
off the ends of the doublet also has maximum gain at high take-off
angles. This means that for short path-length circuits, which require
high take-off angles, a doublet antenna one-quarter wavelength
above ground produces almost omnidirectional coverage.
The vertical plots included for half-wave dipole antennas are given
for heights from 8 to 12 meters. The plot for 8 meters shows that...

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MCRP 6-22D
range of frequencies, normally 2 percent above or below the design
frequency. Since frequency assignments are usually several mega-
hertz apart, it is necessary to construct a separate dipole for each fre-
quency assigned (see figs. 4-11 and 4-12 on page 4-17, and 4-13 on
page 4-19). If space and other resources are unavailable to erect sep-
arate dipoles, three or four dipoles can be combined to occupy the
space normally required for one. 
Each wire...

Antenna Handbook ____________________________ 
4-17Figure 4-11. 8-Meter Half-Wave Dipole (Vertical Pattern).TAKE-OFF ANGLE  3 MHz9 MHz10°10°20°20°30°30°40°40°50°50°60°60°70°70°80°80°90°151050-5-10-51015dBiFigure 4-12. 10-Meter Half-Wave Dipole (Vertical Pattern).TAKE-OFF ANGLE
  3 MHz9 MHz10°10°20°20°30°30°40°40°50°50°60°60°70°70°80°80°90°151050-5-10-51015dBi 

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MCRP 6-22D
fed with an assigned frequency, the doublet cut for that frequency
will radiate the energy. Up to four separate dipoles can be combined
in this manner. When constructing this antenna, examine the indi-
vidual frequency assignments to determine if one frequency is three
times as large as another. If this relationship exists between two fre-
quencies, one dipole cut in length for the lower of the two frequen-
cies will work well for both frequencies....

Antenna Handbook ____________________________ 
4-19
Inverted Vee
The inverted vee, or drooping dipole, is similar to a dipole but uses
only a single center support (see fig. 4-14 on page 4-20). Like a
dipole, it is designed and cut for a specific frequency and has a
bandwidth of 2 percent above or below the design frequency.
Because of the inclined sides, the inverted vee antenna produces a
combination of horizontal and vertical radiation—vertical off the
ends and horizontal broadside to the antenna. All...

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MCRP 6-22D
Characteristics are—
.
Figure 4-14. Inverted Vee Antenna. Frequency range:± 2% of design frequency 
Polarization:Horizontal
Power capability:1,000 watts
Radiation pattern
Azimuthal (bearing):Basically omnidirectional with combi-
nation polarization
Vertical (take-off angle):See figure 4-15 

Antenna Handbook ____________________________ 
4-21
Long Wire
A long wire antenna is one that is long compared to a wavelength
(see fig. 4-16 on page 4-22). A minimum length is one-half wave-
length. However, antennas that are at least several wavelengths long
are needed to obtain good gain and directional characteristics. Con-
structing long wire antennas is simple, and there are no critical
dimensions or adjustments. A long wire antenna will accept powerTAKE-OFF ANGLE  3 MHz9...

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MCRP 6-22D
and radiate it well on any frequency for which its overall length is
not less than one-half wavelength.
The gain and take-off angle of a long wire antenna depend on the
antenna’s length. The longer the antenna, the more gain, and the
lower the take-off angle. Gain has a simple relationship to length;
however, take-off angle is a bit more complicated. A long wire
antenna radiates a cone of energy around the tie wire, much like a
funnel with the antenna...

Antenna Handbook ____________________________ 
4-23
changes as the wire is lengthened. The patterns represent a view
from directly below the antenna.
In the three-wavelength pattern, for very low-angle radiation, posi-
tion the wire somewhat away from the direction of the distant sta-
tion so that the main lobe of radiation points at the receiving station.
If a higher take-off angle is required, point the wire directly at the
distant station. For take-off angles from 5 to 25 feet, the following
general...

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MCRP 6-22D
least one-half of the transmitter power. Terminating resistors are
components of some radio sets but can also be fabricated locally
using supply system components (100-watt, 106-ohm resistor).
Constructing a long wire antenna requires only wire, support poles,
insulators, and a terminating resistor (if directionality is desired).
The only requirement is that the antenna be strung in as straight a
line as the situation permits. The antenna is only 15...