IJA versus IJN Land Based Radar -- They Had Different Systems of Measurement!?!

[Mil-tech Bard]

The Ike Skelton Combined Arms Research Library (CARL) Digital Library has a new digitized copy of the
"Survey of Japanese Antiaircraft Artillery" by the General Headquarters United States Army Forces, Pacific, AAA Research Board

You can download it at this link --

http://cgsc.contentdm.oclc.org/utils/g ... singleitem

Key fact that popped out of "Survey of Japanese antiaircraft artillery" --

The Imperial Japanese Army radar was metric measurement (meters/kilometers).

Imperial Japanese Navy radar was calibrated in _yards_.

That is why the two radars of different services in the same area were different reporting networks. They used different systems of measurement!?!

Can any of the Japanese researchers comment on this fact?

[Mil-tech Bard]

The following is from paragraph 116 of part 2 (IJN) in "Survey of Japanese antiaircraft artillery"

Picket boats. a. Two fleets of picket boats assigned to the Grand
Naval Force, but rnder operational control of the naval sectors, and subject
to specification of patrol area by the Grand Naval Force, formed warning .
screens south of Sasebo and east of Ydkosuka. Each fleet consisted of 60
boats which operated in groups of 20, one group patrolling, one enroute, and
the third outfitting. The boats operated in pairs, and maintained a spacing
of 30 miles between pairs of boats about 400 miles at sea. One boat of each
Pair was eouipped with a Type 13 radar. The boats were gradually driven
toward their bases, and many of them sunk, as our fleet and air activities
increased.

This is the first American document I've seen that stated IJN picket boats off Honshu had radar.

[Wellgunde]

[quote="Mil-tech Bard"]Imperial Japanese Navy radar was calibrated in _yards_.[quote]

Most navies have and still do use yards to measure range and targeting distances. This includes Japan and the U.S. Since Japanese naval optical devices were calibrated in yards, it would have been difficult to integrate a new system calibrated with the metric system.