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AN/SPQ-11 “Cobra Judy“

Description of the radar set, tactical-technical characteristics

Figure 1: The AN/SPQ-11 “Cobra Judy“ S-band radar array is located aft of the “Cobra Judy“ X-band dish under the radome.

Figure 1: The AN/SPQ-11 “Cobra Judy“ S-band radar array is located aft of the “Cobra Judy“ X-band dish under the radome.

Specifications
frequency: 2 900 … 3 100 MHz
(S-Band)
pulse repetition time (PRT):
pulse repetition frequency (PRF): CW … < 400 kHz
pulsewidth (τ): CW … > 50 ns
receive time:
dead time:
peak power:
average power:
instrumented range: > 2 000 NM
(≙ > 3 700 km)
range resolution:
accuracy:
beamwidth:
hits per scan:
antenna rotation:
MTBCF:
MTTR:

AN/SPQ-11 “Cobra Judy“

AN/SPQ-11 “Cobra Judy“ is operating in S-Band shipborne long-range surveillance radar designed to detect and track intercontinental ballistic missiles launched by Russia in their west-to-east missile range. It is mounted aboard the USNS Observation Island (Figure 1) and was designed in 1976. The S-band radar became operational in 1981.

The octagonal passive phased-array antenna, approximately 7 m in diameter, is composed of 12 288 antenna elements. Its transmitter uses 16 traveling wave tubes in a corporate feed structure.

The radar is mounted on an azimuth pedestal. The entire system weighs about 250 tonnes, stands over forty feet high.