Engineering:APS-4
APS-4 radar is a lightweight air to air and air to surface radar.
Design
APS-4 radar is a lightweight air to air and air to surface radar with a detection range for large ships of circa. 15 miles, and for an aircraft, about 5 miles. It could also detect coastline at approximately 75 miles.[1]
Physically, the APS-4 consists of a control box, one or two indicators, the same number of indicator-amplifiers, an antenna, a transmitter-receiver, and a cable junction box.[2] The antenna and transmitter-receiver were typically housed externally below one wing, in a fiberglass shape that was similar to a Mk 17 500 pound bomb.[3] These displays could be set for ranges of 4, 20, 50, and 100 nautical miles (6, 30, 80, and 160 km).[4] The radar weighed 180 lbs.[4]
The APS-4 broadcast in the X-band with a wavelength of 3 cm.[4][2] Peak brodcast power varied from 40 to 70 kW according to radar version. Pulse repetition frequency was adjustable by the operator to either 600 or 1000 cpS. [5]
The APS-4 emitted a radio beam in the form of a 6° cone. The beam could be directed in three modes, manual, search and intercept. In manual mode the beam was aimed by operator control from 10° above, to 30° below the longitudinal axis of the aircraft. In search mode, the radar beam scans through 150° in azimuth, and while doing so would run two lines scans, each separated by 4°. This caused the beam to cover 10° in a vertical plane. In intercept mode, the beam executes a four-line scan, with 6° between lines, to cover a vertical plane of 24°.[3] Results were displayed on one or two 3-inch displays.[2]
An improved version was called the AN/APS-5. A simplifed version for single seat fighters was called the APS-6.[6]
References
- ↑ http://pwencycl.kgbudge.com/A/s/ASH_airborne_radar.htm>
- ↑ 2.0 2.1 2.2 "HyperWar: Tactical Uses of Radar in Aircraft (RADTWOA) [Part II"]. https://www.ibiblio.org/hyperwar/USN/ref/RADTWOA/RADTWOA-2.html#an/aps4.
- ↑ 3.0 3.1 https://www.aef.se/Avionik/PDF-filer/PS18_USN_APS-4_Tactical_use.pdf
- ↑ 4.0 4.1 4.2 Budge, Kent G.. "The Pacific War Online Encyclopedia: ASH Airborne Radar". http://pwencycl.kgbudge.com/A/s/ASH_airborne_radar.htm.
- ↑ "Duxford Radio Society: Restoration: Radar APS-4". http://www.duxfordradiosociety.org/restoration/equip/aps4/aps4.html.
- ↑ Budge, Kent G.. "The Pacific War Online Encyclopedia: APS-6 Airborne Radar". http://pwencycl.kgbudge.com/A/p/APS-6_airborne_radar.htm.
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