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Letter from Bruce T. Neale, Marconi Radar Systems Ltd., to Martin Shough 4 Dec 1986

Marconi Radar Systems Limited
Writtle Road
Chelmsford CM1 3BN
Telephone: 0245 267111 Telex: 99108 Facsimile: 0245 357927

4th December. 1986.

Dear Martin.

I acknowledge your letter dated 15th November, 1986. Thank you for returning the photographs and extra copies. I will attempt to answer your questions in order:-

l. The Type 13/14 handbooks do not give the altitude/range performance (cover diagrams). The beam shapes are approximately as previously stated, i.e.: Type 13/14 Mk. 7 use a single curvature, parabolic reflector giving a 'pencil' beam and the Type 14 Mk. 8 has a specially shaped reflector giving an approximate cosec2 pattern in the vertical plane. The polar diagrams are far from ideal, having sidelobes in the order of -14 dB due, largely, to the antenna feed support structure. Please remember that the antenna was based on a wartime design when antenna theory had not been fully developed.

2. The term 'Happidrome', I believe, was adopted from a popular wartime radio show of that name. It is not an acronym.

3. With regard to Sector Scanning, the Type 14's were capable of position control and sector scanning having an Amplidyne servo-mechanism, but not the Type 7 which used a Ward-Leonard system.

In the event, sector scan was rarely used as the wear and tear on the turning gear was considerable. There was little merit in it anyway, the time used to decelerate and accelerate the large mass was a considerable portion of the rotation time. It was more efficient to leave it in continuous rotation, usually synchronised to the Type 7.

4. We do not know much about the AN-CPS5 other than it is a medium range ATC radar made by Bendix. The reference to G.E.C. can only mean U.S. General Electric, we in G.E.C. had no hand in it.

5. M.T.I, was not used on Type 13 or Type 14, the inherent stability of the radar being inadequate for this purpose. M.T.I. techniques (delay lines, phase sensitive detectors, etc.) had not been fully developed at this time. The first U.K. radar to use M.T.I, operationally was developed from the wartime Type 11 on 600 MHz. later to become the Marconi S.232 and S.264 used world-wide as an ATC radar.

6. Your question regarding radar range performance in relation to P.R.F., Scan Rate, Target Cross-section, etc., etc., is, as I am sure you will appreciate too complex to answer simply in a letter. May I refer you to: "Introduction to Radar Systems" by Merrill Skolnik and published by McGraw-Hill in paperback. Alternatively, I recommend "Understanding Radar" by a colleague of mine, Henry Cole, recently published by Collins (under 10). I enclose order form!

I hope the above will be of use to you. I apologise for ducking out of the range question, but as you will discover from Skolnik, it is dependent on so many interactive variables.

Yours sincerely,

s/s Bruce Neale