Description of the radar set, tactical-technical characteristics
Figure 1: AN/SPN-4
|frequency:||3 010 … 3 100 MHz
|pulse repetition time (PRT):|
|pulse repetition frequency (PRF):||1 000 Hz|
|pulsewidth (τ):||0.4 µs|
|peak power:||15 kW|
|average power:||6 W|
|instrumented range:||50 NM (≙ 90 km)|
|range resolution:||90 m|
|hits per scan:|
|antenna rotation:||7 rpm|
AN/SPN-4 is operating in the S-Band navigational radar designed for non-combatant ships.
The antenna is a cut paraboloidal reflector 7 feet wide and 1 foot high, fed with a horn radiator. It uses horizontal polarization. The vertical beam width is 13.5 degrees. The antenna mounts on a rotating pedestal which houses the drive mechanism. RF energy may be fed to or from the antenna by means of a coaxial cable or a waveguide. When the distance from the transmitter/receiver to the antenna is less than 20 feet, a 50-ohm coaxial cable may be used.
- Military Standardisation Handbook TM 11-487C-1/MIL-HDBK-162A, Band 1, p. 1166