Center-Fed Dipole
The center-fed dipole (fig. 2-27) is designed for
use at an average power rating of 100 watts. All major
components of the radiating and support structures
are aluminum. The central feed section and radiating
elements are protected by a laminated fiberglass cover.
Center-fed dipole antennas range from 29 to 47 inches
in height and have a radiator diameter of up to 3
inches.
Coaxial Dipole
Figure 2-28 shows two types of coaxial dipoles.
The coaxial dipole antenna is designed for use in the
uhf range, with an rf power rating of 200 watts. The
Figure 2-27.—AS-2809/RC center-fed dipole antenna.
AT-150/SRC (fig. 2-28, view A) has vertical radiating
elements and a balun arrangement that electrically
balances the antenna to ground.
Figure 2-28, view B, shows an AS-390/SRC
antenna assembly.
This antenna is an unbalanced
broadband coaxial stub antenna. It consists of a
radiator and a ground plane. The ground plane (or
counterpoise) consists of eight elements bent downward
37 degrees from horizontal. The lower ends of the
elements form points of a circle 23 inches in diameter.
The lower section of the radiator assembly contains
a stub for adjusting the input impedance of the antenna.
The antenna is vertically polarized, with an rf power
rating of 200 watts, and a vswr not greater than 2:1.
SATELLITE SYSTEMS
The Navy Satellite Communication
(SATCOM) provides communications
System
links,
via satellites, between designated mobile units and
shore sites. These links supply worldwide communica-
tions coverage. The following paragraphs describe
some of the more common SATCOM antenna systems
to which you will be exposed.
AS-2815/SRR-1
The AS-2815/SSR-1 fleet broadcast receiving
antenna (fig. 2-29) has a fixed 360-degree horizontal
pattern with a maximum gain of 4 dB at 90 degrees
from the antenna’s horizontal plane. The maximum
loss in the antenna’s vertical pattern sector is 2 dB.
The vswr is less than 1.5:1, referenced to 50 ohms.
This antenna should be positioned to protect it from
interference and possible front end burnout from radar
and uhf transmitters.
ANTENNA GROUPS OE-82B/WSC-1(V)
AND OE-82C/WSC-1(V)
Designed primarily for shipboard installations, these
antenna groups interface with the AN/WSC-3
transceiver. The complete installation consists of an
antenna, bandpass amplifier-filter, switching unit, and
antenna control (figs. 2-30 and 2-31), Depending on
requirements, one or two antennas may be installed
to provide a view of the satellite at all times. The
antenna assembly is attached to a pedestal that permits
2-16
