Форум "ВТОРАЯ МИРОВАЯ ВОЙНА 1939-1945 гг."

Из Фридмена.
Japan

DESIGNATIONS

Japanese designations were based on the year the set entered service, in terms of the Japanese imperial calender, in which 1940 was the year 2600 (ie the year zero in the single-digit form generally used). Within a year, mark numbers identified sets, so that Type 2 Mks 1 and 2 were two sets of 1942. Within each mark was a model ('Mod') series. Prototypes had their own mark series, as they received no type numbers until service introduction; airborne (as opposed to shore/ship) sets had a separate series. Changes within a Mod were identified by 'Kai' (modification) numbers, ie Type 2 Mk 2 Mod l-Kai-3. As an added element of confusion, prototypes sometimes entered service without receiving type numbers (cf the US CXAM).

The Japanese themselves often referred to sets by mark/model only, eg '21' for Mk 2 Mod 1 (without any reference to the type).

RADARS

Type 2 Mk 1

The first Japanese radar, a 3m, 5kW shore-based air search set (Mod 1), using two antennas to achieve a maximum effective range of about 80nm. Work began in April 1941, and was not based on captured Allied equipment.

Type 2 Mk 2

Work began in October 1941, on the basis of a 500W magnetron operating at 10cm. Development of the Mod 1 Kai-2 version was completed in August 1943, using a 1.5m wavelength, with a peak power of 5kW (10-microsecond pulses, PRF 1000). The antenna was a 4 x 3 dipole mattress (4x4 in the Kai-4 version) 6 x2m in dimensions and with a 34° x 60° beam. Range was 70-100km (38-54nm); accuracy was l-2km and resolution 2km and 20°; and weight was 840kg. The original Mk 2 Mod 1 was developed for converted mechant ships (January-April 1942); Kai-2 was ready in December 1942, and a Kai-3 for combined air and surface search was developed between August 1943 and February 1944 but was withdrawn from service. Typically Mk 2 was mounted on the foretop of a battleship, or in a rotating installation aboard carriers.

Type 3 Mk 1

Derived from a land-based set of 1943, development being completed in February 1944. It operated at 2m, with a peak power of 10kW (10-microsecond pulses, PRF 500), using a 2 x 4 dipole mattress (2 x 4m, with a 68° x 35° beam) to achieve a range of 50-100km (27-54nm). Accuracy was 2-3km and 10° and resolution 3km and 60°, with a total weight of 110kg. Typically it was mounted fixed on both sides of a battleship mainmast. Data refer to Mod 3.

Mk 2 Mod 2

A microwave surface search radar, using a horn antenna 0.4m in diameter, and operating at 10cm. It retained its original experimental designations; development was completed in December 1943. Peak power was 2kW, with a pulse-length of 10 microseconds and a PRF of 2500, and the beam was conical, 38° x 38°, with a range of 25km (13nm) on a batdeship. Accuracy was 0.1-0.25km and 3°, and resolution 1.5km and 40°.

Total weight was 1300kg. It was designed from the outset for shipboard use, but was not considered as reliable as the simpler metric Type 3 Mod 1. Mk 2 Mod 2 employed separate transmitting and receiving horns, and was originally designed for submarine use.