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AN/SPQ-9A

The AN/SPQ-9A is a multi-purpose U.S. naval radar, used in conjunction with the AN/SPG-60 radar for the Mk 86 fire control system. This combination provides surface search and low-level air coverage (up to 2,000 ft). The radar supports defenses against high-speed (up to Mach 3), low-flying missiles or aircraft, and allows the tracking of helicopters.

The radar operates in a high-resolution, pulse-Doppler, track-while-scan mode. High scan rate of 60 rpm provides a 1-second "data rate" (producing a new image of the scanning area every second) to detect and more accurately track incoming missiles as well as surface targets.

The SPG-9A provides pulse-to-pulse frequency-agility with a choice of five frequencies to counter jamming and natural clutter, and to allow several radars to operate in a cluster without interfering with one another. An optional digital Moving Target Indicator (MTI) is available to remove stationar y objects from the target screen, reducing clutter; for use primarily against shore targets.

Range is from 150 yds (137 m) to 20 nm (37 km). Although the basic capacity is four simultaneous targets, the Mk 86 can handle up to 120 targets in the track-while-scan mode. This permits weapons to shift rapidly from one target to another. The radar can be integrated with the Naval Tactical Data S ystem (NTDS).

The SPQ-9A includes a separate radar beacon transmitter-receiver for accurate navigation during indirect shore bombardment, when the target is out of view of both the radar and optical sighting systems. It communicates with ground-based radio beacons such as the AN/TPN-7, AN/TPN-16 or AN/UPN-32.

CHARACTERISTICS

 Weight:
    antenna            1,185 lbs (537 kg) (including radome)
 Dimensions:
  antenna
    length              4 ft 5 in (1.3 m)
    width               5 ft 9 in (1.8 m)
  radome
    length             10 ft      (1.3 m)
    width               8 ft      (1.7 m)
 Band:
                       I (8-10 GHz)
 Beam:
                       1.35 x 3 deg.
 Peak Power:
                       1.2 kW
 Gain:
                       37 dB
 Pulse Width:
                       0.3-16 microseconds
 Pulse Repetition Frequency (PRF):
                       3,000 pps
 Scan Rate:
                       60 rpm

There are two versions of the radar antenna: The basic system provides low altitude air search (2,000 ft/610 m) and surface search functions, and is enclosed by a radome; the other adds Identification Friend or Foe (IFF) and extends air coverage to an elevation of 25 deg.

Source:  periscope.com