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

Chapter 7
Satellite Communications Antennas
The Marine Corps’ primary LOS and SATCOM radio set, the AN/
PSC-5 enhanced manpack UHF terminal, operates at 5 to 25 kHz
and provides data and voice communications. It replaces all man-
packable and vehicular-mounted UHF SATCOM radios. The AN/
PSC-5 provides LOS communications with the AS-3566 and long-
range SATCOM with the AS-3567 and AS-3568 antennas.
Characteristics of the AS-3566 (fig. 7-1) are—
Frequency range (LOS):30 to 400 MHz
Demand assignment...

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Characteristics of the AS-3567 (fig. 7-2) are—
Frequency range:225 to 399.995 MHz
Beamwidth:85°
Orientation:Directional
Elevation (0 to 90°)
Input impedance:50 ohms
VSWR:1.5:1
Gain:6 dB (225 to 318 MHz)
5 dB (318 to 399.995 MHz)Figure 7-2. AS-3567 Medium-Gain Antenna. 

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Characteristics of the AS-3568 (fig. 7-3) are—
Frequency range:240 to 400 MHz
Beamwidth:77°
Orientation:Directional
Elevation ( 0 to 90°)
Azimuth:  ± 180°
Imput impedance:50 ohms
VSWR:1.5:1 maximum
Gain:8 dB (240 to 318 MHz)
6 dB (318 to 400 MHz)
PowerUp to 150 watts continuousFigure 7-3. AS-3568 High-Gain Antenna. 

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 SITING SATCOM ANTENNAS
The most important consideration in siting LOS SATCOM equip-
ment is the antenna elevation with respect to the path terrain.
Choose sites that exploit natural elevations.
Considerations
The most important consideration in siting over-the-horizon sys-
tems is the antenna horizon angles (screening angles) at the termi-
nals. As the horizon angle increases, the transmission loss
increases, resulting in a weaker received signal....

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7-5
Trees, buildings, hills, or the Earth can block a portion of the UHF
signal, causing an obstruction loss. To avoid signal loss due to
obstruction and shielding, clearance is required between the direct
LOS and the terrain. Path profile plots are used to determine if there
is adequate clearance in LOS systems.
Weak or distorted signals may result if the SATCOM set is operated
near steel bridges, water towers, power lines, or power units.  The
presence...

Chapter 8
Antenna Farms
The antenna farm (also referred to as the radio hill or the antenna
hill) is a component of a command echelon. It is the location of the
bulk of the unit’s antennas and radio and cryptographic equipment.
It is also the portion of the command echelon that produces the
majority of the electromagnetic radiation. Antenna farms can be
located in several different areas: inside the command echelon, out-
side the command echelon but near it, or outside the command ech-
elon but far from...

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Main
The main echelon is where the commander is normally located
together with those elements of the staff required to plan and direct
operations and control forces. The antenna farm will generally be
located outside of and far from the CP.
Rear
The rear echelon, located to the rear of the main echelon, focuses on
administrative and logistics functions. It is normally established by
regiments and larger units. It may be located in or near the rear...

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Communications
• Take a radio along on reconnaissance to ensure that communi-
cation from the proposed site is possible.
•  Choose another site if communication is not possible.
Electronic Warfare
• Enemy capability.
•  Projected electronic signature of the command. 
Tactical Situation
• Cover and concealment.
• Offense/defense.
• Moving/static.
• Intended length of stay.
• Future operational plans.
•  Speed of displacement.
Accessibility
• Terrain.
•...

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antenna farm location decision. At the division/force service sup-
port group/wing levels, the antenna farm should be remoted 1,000
meters away from the CP, if possible.
Security. The antenna’s physical security depends on the ability to
protect it. The requirement to provide protection depends on the
considerations listed above. Protection considerations also depend,
in part, on the proximity of the antenna farm to the CP. For an
antenna within the...

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from the site. A thoroughly covered and concealed site that prevents
communications is worthless.
Obstacles. As with any other defensive position, use natural or
manmade obstacles to enhance the antenna farm’s security.
Terrain. Studying the terrain in the vicinity of remote antenna farms
is essential to developing an adequate plan for defense. Studying
the terrain is also of paramount importance to ensuring that a unit
can communicate from the site....