Description of the radar set, tactical-technical characteristics
Figure 1: AN/SPN-21
|frequency:||9 335 … 9 405 MHz
|pulse repetition time (PRT):|
|pulse repetition frequency (PRF):||750 or 1 500 Hz|
|pulsewidth (τ):||0.2 µs|
|peak power:||7 kW|
|instrumented range:||32 NM (≙ 60 km)|
|range resolution:||45 m|
|hits per scan:|
|antenna rotation:||20 rpm|
AN/SPN-21 was operating in X-Band short-range navigation and surface surveillance radar designed for small boats. It is a modified military version of the Raytheon Pathfinder Model 1500 from the mid-1950s. The radar was renamed in AN/SPS-35 later.
The single curved parabolic reflector was 53 inches wide (≙ 1.32 m). It formed a fan beam pattern with a vertical beam width of 15° to 18°. The antenna, transmitter, and receiver of are an integral unit.