Jodrell Bank Observatory: 71MHz Searchlight Aerial

The 71MHz Searchlight Aerial at Jodrell Bank Observatory is a Grade II listed structure, originally a Second World War trailer-mounted searchlight base that was converted into a searchlight aerial in 1946 by John Atherton Clegg.

The structure is made of steel, steel scaffolding poles, and concrete. It features a steel trailer-mounted chassis that is aligned approximately east-west. The wheels have been removed, and the chassis is secured to a concrete plinth measuring about 3 meters by 3 meters (9 feet 9 inches by 9 feet 9 inches). On top of the chassis is a circular, revolving mount, which is unlikely to function now due to its poor condition.

Flanking the plinth are two long, narrow concrete channels, each approximately 600 millimeters (2 feet) wide and of similar depth. These channels, which are now overgrown and filled with water and trees, extend for about 17 meters (21 feet 3 inches), with one channel running east and the other west. On the south side of the structure, there is an arc of partially obscured hard-standing that may indicate the range of rotation for the aerials.

It is important to note that the two large I girders and the associated bolted L-shaped girders resting on timbers across the top of the mount are not part of the original structure. The exact location of the searchlight aerial is approximate, as it is not shown on modern digital mapping and its outline is unclear due to vegetation.