I am trying to determine what this concrete structure was used for. Dimensions : 15ft external width 111in internal width pedestal in the middle is 16in square. I have found this image linked below, stating its an anti-aircraft installation. http://www.alamy.com/stock-photo-remnants-of-wwii-anti-aircraft-installations-next-to-halnaker-windmill-26344914.html If that is the case what weapon was mounted to this base.
This chap thinks it may be the base of an HFDF/RDF tower: http://www.derelictplaces.co.uk/main/military-sites/19924-halnaker-hill-radio-direction-finding-station-2011-a.html#.WJ9Iqn9UUYE Also mentions searchlight as a possibility: https://historicengland.org.uk/listing/the-list/list-entry/1020514
Possibly an Observer Corps site. The pedestal in the middle would mount the direction/angle instrument you see in the pictures of the time. Technically it would be an AA site.
