File:GL Mk IIIc radar Accurate Position Finder.jpg

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GL_Mk_IIIc_radar_Accurate_Position_Finder.jpg(387 × 291 pixels, file size: 62 KB, MIME type: image/jpeg)

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Summary

Description
English: The GL Mk. III was a microwave-frequency Gun Laying radar that fed information directly to a predictor to calculate the angle and fuse delays for an associated battery of anti-aircraft guns. Using radars of this sort reduced the number of shells fire to get a "hit" from about 41,000 in the pre-war era, to about 1000 using the Mk. III.

This image shows the Canadian version of the GL Mk. III, the Mk. III(C). It came in two halves, the APF, Accurate Position Finder, shown here, and the ZPI, Zone Position Indicator, not shown. The ZPI was a wide-angle search system that cued the APF operators to the rough location of the target. A generator set, seen on the left, fed power to both radars.

Mk. III was designed in the era before it was possible to quickly switch microwave frequencies, and so both the Canadian and British models of the Mk. III both feature two antennas and their associated parabolic reflectors, one used for transmission and the other reception. One easy way to tell the two models apart is the flat edges of the reflectors, seen only on the Canadian version.

Mk. III was also designed before there was a way to feed microwaves through cables to a rotating antenna. Instead, the entire operators cabin rotated to track targets, and can be seen to be slightly off-centered in this photo. The antennas "nodded" up and down to track in elevation, and for transport the entire assembly could be rotated forward and locked into the bracket seen projecting from the front of the cabin.

Both of these limitations were soon addressed, switching through the use of the soft Sutton tube and rotation through the move to waveguides instead of coaxial cables, leading to the dramatically superior US SCR-584. The -584 became widely used starting in 1944, and the Mk. III's were generally relegated to secondary roles.
Date circa November 1943
date QS:P,+1943-11-00T00:00:00Z/10,P1480,Q5727902
Source https://www.flickr.com/photos/museenavaldequebec/4435376316/
Author Unknown Canadian Air Force personnel

Licensing

Public domain This Canadian work is in the public domain worldwide because it was subject to Crown copyright and was first published before December 31, 1974.

According to Public Works and Government Services Canada / Travaux publics et Services gouvernementaux Canada, Canada has no intention of renewing expired Crown Copyright works in any country, and consequently the URAA does not apply. An email is on record at ticket:2013122310013986.


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Date/TimeThumbnailDimensionsUserComment
current16:40, 20 November 2014Thumbnail for version as of 16:40, 20 November 2014387 × 291 (62 KB)Maury MarkowitzUser created page with UploadWizard