Use of one cable-wrap meter for indicating cable wrap on the antenna reduces cable conductor
requirements, permits mounting the meter on the same panel with the antenna indicators, and simplifies operator
Reference phase current for all synchros must be supplied from a common phase source.
SYSTEM THEORY OF OPERATION
GENERAL (See Figure 1-2) - The Antenna System is installed in an inflatable radome and has azimuth and
elevation rotation capabilities. The Antenna System and associated control units allow an area in space to be searched
(1) Operation of the Antenna System is possible in three modes - manual, slave or scan. In either of the
three modes, positioning of the antenna is controlled by two identical channels, an azimuth channel and an elevation
channel, each of which is capable of receiving control voltages from a local or remote source and converting these
voltages into azimuth and elevation positioning data. In addition, the azimuth channel may be controlled by voltages
originating in a scan generator in the Control Indicator. In the manual mode of operation, the antenna is positioned by a
60-cps control voltage generated by handwheel-driven synchros. In the slave mode of operation, the antenna and
counters on the Control Indicator are positioned by a 60-cps control voltage from a remote source. In the scan mode of
operation, the antenna scans a predetermined sector in azimuth in response to control voltages generated by the scan
generator. In this mode, the elevation positioning circuit functions as in the manual mode.
(2) Synchro outputs, which are proportional to the azimuth and elevation angles of the antenna, with respect
to zero-degree azimuth and elevation reference points, are provided by the Antenna System.
(3) The direction of true heading is relative to a furnished reference line and earth stable coordinates. The
azimuth orient controls on the Antenna Position Power Supply allow a compensation factor to be set into the system for
misorientation of a system to the established references.
(4) Figure 1-2 is an overall block diagram of the QRC-280(A) Antenna System which indicates the major
functional components of the Antenna System and the relationship of these components to the control units. The
Antenna Control Power Supply provides operating power, servo excitation, and azimuth
Revised January 22, 1968