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AN/SPS-3

Description of the radar set, tactical-technical characteristics

Figure 1: AN/SPS-3, Drawing of the antenna unit

Figure 1: AN/SPS-3, Drawing of the antenna unit

Specifications
frequency: 9 003 … 9 168 MHz, and
9 345 … 9 405 MHz
( X-Band)
pulse repetition time (PRT):
pulse repetition frequency (PRF): 3000 or 1500 Hz
pulsewidth (τ): 0.25, 0.33 or 1.33 µs
receive time:
dead time:
peak power: 2×200 kW
average power:
instrumented range: 25 NM (≙ 46 km)
range resolution:
accuracy:
beamwidth:
hits per scan:
antenna rotation:
MTBCF:
MTTR:

AN/SPS-3

The AN/SPS-3 was an early post-WWII, short range, X-Band naval radar for use on destroyers and larger vessels. It was a hemispherical search radar and utilizes two rapid scanning pencil-type antenna beams, each covering a 40-degree elevation angle sector and full 360-degree azimuth. Slightly different frequencies are used for the two beams (frequency diversity). Each beam had its own transmitter, receiver and waveguide system, but only one antenna system, using a dual Foster Scanner, was required.

The modulator was of the hydrogen thyratron type and was capable of pulsing both magnetrons simultaneously by use of a special dual type pulse transformer. The magnetrons were types 4J50 and 4J78. A so-called synchroscope unit (combined synchronisator and display) containing a 5-inch cathode ray tube and associated circuits was capable of presenting video, trigger, modulator pulse, and STC voltages, as well as functioning as an A-scope with 1/2, 5 and 25 miles sweeps.

It was installed as a pre-production prototype (XN-1) on the USS Northampton CLC-1 in 1954. After this one installation the AN/SPS-3 program was cancelled.

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