AN/SPS-49

The AN/SPS-49 is a United States Navy two-dimensional, long range air search radar built by Raytheon that can provide contact bearing and range. It is a primary air-search radar for numerous ships in the U.S. fleet and in Spain, Poland, Taiwan aboard Oliver Hazard Perry-class frigates, Canada on its Halifax-class frigates, New Zealand on its Anzac-class frigates and Australia on its Adelaide-class frigates and Anzac-class frigates. It also serves in a complementary role aboard Aegis cruisers with the AN/SPY-1.

Operation
First tested in 1965 aboard USS Gyatt (DD-712) and introduced in 1975, the AN/SPS-49 operates in the 851–942 MHz, or L-, band and has a range of 256 nmi. The orange-peel parabolic shape of the antenna creates a narrow 3.3°-beam to reduce the probability of detection or jamming. It can rotate at 6 rpm in long range mode or 12 rpm in short-range mode. Default is at 12 rpm for the AN/SPS-49A(V)1, to provide more frequent scans against incoming missiles. The SPS-49A(V)1 can detect out to its full range at either 6 or 12 rpm. The antenna is stabilised to compensate for ships pitch and roll, to a maximum of +/-15° for both pitch and roll in 12 rpm mode, and +/-23.5° for both pitch and roll in 6 rpm mode. The output stage of the transmitter in all variants uses a two-cavity klystron amplifier.

Variants
As of 2010, there are eleven configurations of the AN/SPS-49(V).
 * AN/SPS-49(V)1 - Baseline radar (Various CVN, LHA, LSD and other ships)
 * AN/SPS-49(V)2 - (V)1 radar without the coherent side  lobe  cancellation feature (Oliver Hazard Perry-class frigates)
 * AN/SPS-49(V)3 - (V)1 radar with the radar video processor  (RVP)  interface (FC-1) (USS Long Beach (CGN-9))
 * AN/SPS-49(V)4 - (V)2 with  the  RVP interface (Oliver Hazard Perry-class frigates)
 * AN/SPS-49(V)5 - (V)1 with automatic target detection  (ATD) (New Threat Upgrade (NTU) ships)
 * AN/SPS-49(V)6 - (V)3 system with double shielded cables and a modified cooling system (USS Ticonderoga (CG-47))
 * AN/SPS-49(V)7 - (V)5 system with a (V)6 cooling system (Aegis combat system)
 * AN/SPS-49(V)8 - (V)5 system enhanced to include the AEGIS Tracker modification kit (Aegis combat system)
 * AN/SPS-49(V)8 ANZ - (V)8 system modified to interface with the CelsiusTech 9LV-453 combat system (Anzac-class frigates)
 * AN/SPS-49(V)9 - (V)5 with medium PRF upgrade (MPU)
 * AN/SPS-49A(V)1 - Developed in the mid-1990s. Added radial speed determination on each target, each scan. Improved clutter rejection