Trials Equipment

The airborne platform was a Shackleton VW126 fitted with a coherent three channel radar receiver.  The reference signal was received by a microwave antenna fitted in the front radome and the signal to be measured received through a static split trainable dish fitted in the rear turret.

The receiver was housed in standard racks, located on the right hand side of the aircraft in the crew compartment.

To illustrate the above photo was taken inside a Shackleton MR3, with somewhat different configuration.  The equipment racks replaced the galley, just visible on the right.  The bunks on the left, were not there instead there were more rows of the side-by-side seating one can see in the center of the photo. The recording camera was mounted on one such seat.



Shackelton seating.jpg

The team leader operated from the chair visible through the hatch way. See photo below.

Green Flax - Trials Malvern, April 1957 - Courtesy  - Defford Airfield Heritage Group

Green Flax – Trials Malvern, April 1957 – Courtesy – Defford Airfield Heritage Group

The receiver construction was entirely modular, all valve.  The modules (amplifies, VCOs, mixers, phase shifters etc) were all plug in and painted black. Practical easy to maintain and service.

The three channel receiver (sum, and left right, up down difference) could track the various airborne targets involved in the trial. And the received signals shifted down to baseband, displayed through a spectrum analyser.

The Spectrum analyser output was displayed on a CRT and photographed using an automatic feed 35mm camera.

The whole system was regularly calibrated so that the amplitude of the spectral components could be read of by the team in Film Analysis back at Luton.

From memory calibration was via a test set, which calibrated the receiver in situ. Providing a reference signal to the front antenna and a calibrated signal to the rear dish from a horn antenna, mounted on a stand set a standard distance from the real of the plane.  The Mount allowed for lateral movement of the horn for measurement of the dish polar diagram.


Ground Equipment 


The Ground radar was a modified version of the Red Brick radar, used by the Thunderbird 1 GW system.  The modification would have been the addition of the CW illuminator.  This version probably code named Blue Label. Which evolved into the Type 86 Radar (Indigo Corkscrew) representative of the illuminator radar used through the trials , adjacent to Defford and Portland.  Manned by Jeff Marshall and Stan Brown.

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