coupler group permits several transmitters to operate
simultaneously into a single, associated, broadband
antenna, thus reducing the total number of antennas
required in the limited space aboard ship.
These antenna coupler groups provide a coupling
path of prescribed efficiency between each transmitter
and the associated antenna. They also provide isolation
between transmitters, tunable bandpass filters to
suppress harmonic and spurious transmitter outputs,
and matching networks to reduce antenna impedances.
The three antenna coupler groups (AN/SRA-56,
-57, -58) are similar in appearance and function, but
they differ in frequency ranges. Antenna coupler group
AN/SRA-56 operates in the 2- to 6-MHz frequency
range. The AN/SRA-57 operates from 4 to 12 MHz,
and the AN/SRA-58 operates from 10 to 30 MHz.
When more than one coupler is used in the same
frequency range, a 15 percent frequency separation
must be maintained to avoid any interference.
Antenna Coupler Group AN/SRA-33
Antenna coupler group AN/SRA-33 operates in
the uhf (225-400 Mhz) frequency range. It provides
isolation between as many as four transmitter and
receiver combinations operating simultaneously into
a common uhf antenna without degrading operation.
The AN/SRA-33 is designed for operation with
shipboard radio set AN/WSC-3. The AN/SRA-33
consists of four antenna couplers (CU-1131/SRA-33
through CU-1134/SRA-33), a control power supply
C-4586/SRA-33, an electronic equipment cabinet
CY-3852/SRA-33, and a set of special-purpose cables.
OA-9123/SRC
The OA-9123/SRC multicoupler enables up to four
uhf transceivers, transmitters, or receivers to operate
on a common antenna. The multicoupler provides
low insertion loss and highly selective filtering in each
of the four ports. The unit is interface compatible
with the channel select control signals from radio sets
AN/WSC-3(V) (except (V)1). The unit is self-
contained and is configured to fit into a standard
19-inch open equipment rack.
The OA-9123/SRC consists of a cabinet assembly,
control power supply assembly, and four identical filter
assemblies.
This multicoupler is a state-of-the-art
replacement for the AN/SRA-33 and only requires
about half of the space.
RECEIVING ANTENNA
DISTRIBUTION SYSTEMS
Receiving antenna distribution systems operate
at low power levels and are designed to prevent
multiple signals from being received. The basic
distribution system has several antenna transmission
lines and several receivers, as shown in figure 2-38.
The system includes two basic patch panels, one that
terminates the antenna transmission lines, and the other
that terminates the lines leading to the receivers. Thus,
any antenna can be patched to any receiver via patch
cords.
Figure 2-38.—Receive signal distribution system.
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