The Pacific War Online Encyclopedia: FD Fire Control Radar (original) (raw)
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The Pacific War Online Encyclopedia | |
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National Archives #19-N-30722
Cropped by author
FD Mark 4
| Wavelength | 40 cm |
|---|---|
| Pulse Width | 1.5 microsecond |
| Pulse Repetition Frequency | 1640 Hz |
| Power | 15-20 kW |
| Range | 12,000 yards (11,000m) on 5" (127mm) shell splash40,000 yards (37,000 meters) on bomber12,000 yards (11,000 meters) on submarine20,000 yards (18,000 meters) on destroyer30,000 yards (27,000 meters) on battleship |
| Scope | A scope |
| Accuracy | 40 yards (37 meters)4 mils |
| Resolution | 1500 feet (460 meters)10 degrees |
| Production: | 667 sets from 1941 to 1944 |
FD Mark 12
| Wavelength | 33 cm |
|---|---|
| Pulse Width | 1.2 microsecond |
| Pulse Repetition Frequency | 480 Hz |
| Power | 100-110 kW |
| Range | 45,000 yards (41,000 meters) on bomber40,000 yards (37,000 meters) on battleship |
| Scope | A scope |
| Accuracy | 15 yards (14 meters)/3 mils |
| Resolution | 300 feet/7degrees |
| Production: | Used on Mark 37 directors for 5"/38 gunsstarting in 1944 |
The U.S. FD fire control radar was known in Britishservice as the Type 285. It was similar to FCbut had a larger antenna and gave altitude information. The antenna was a stabilized 6' by 6' (1.8m by 1.8m) double reflector with 2x4 dipoles and the display was an "A" scope with a 100,000 yard (91,000 m) range scale.
An improved version, the Mark 12, used the same antenna but an improved set. The Mark 12 also incorporated a Mark 22 low angle height finding radar. Its "A" scope used a 50,000 yard (45,000 m) range scale.
References
The Pacific War Online Encyclopedia © 2007-2009 by Kent G. Budge. Index
