Figure 2-4.AN/SPS-55 block diagram.
receiver-transmitter (R/T), the radar set control (RSC),
and the antenna safety switch.
Although the AN/SPS-55 radar is electronically
reliable, the antenna pedestal has been a source of
mechanical maintenance problems. A field change kit,
developed in FY89, provided an improved antenna
Delivery and installation of the pedestal
modification are coordinated by the Restoration
SIGNIFICANT INTERFACES. The AN/SPS-
55, like all radars, has an impact on other systems,
subsystems, and equipment. The RVC modification
developed for the FFG-61 and the antenna pedestal
modification not only improved the radar set, but
improved the interface capabilities. The RVC enables
the FFG-61 Integrated Automatic Detection and
Tracking System (IADT) to use the AN/SPS-55 data.
The pedestal modification allows interface with IFF.
The AN/SPS-55 interfaces with the following
Blanker/Video Mixer Group, AN/SLA-10
Indicator Group, AN/SPA-25( ) or equivalent
Mk 27 synchro signal amplifier or equivalent
Mk XII IFF (pedestal mod only)
AN/SYS-2(V)2 IADT (FFG-61 RVC mod only)
FOR THE MAINTAINER. The AN/SPS-55
radar has various built-in features to protect the
maintainer and the equipment. The transmitter has a
voltage standing wave ratio (vswr) alarm. Fault
detection indicators, located on both the transmitter and
the RSC unit, show when the high-voltage power
supply, modulator, or magnetron exceeds predetermined
safe limits. A low-power condition in the radar
automatically places the radar in the standby mode and
activates an indicator at the RSC when low power exists.
The antenna safety switch, when activated, opens
the radiate interlock, removing power from the drive
motor. It also activates a Man Aloft indicator on both
the R/T and the RSC unit to ensure that no one tries to
operate the radar during maintenance.
Maintenance of the AN/SPS-55 consists primarily
of module replacement, with limited repair or
replacement of certain individual components. The
equipment is designed for rapid fault isolation to the