Sitting on top of the hill, with the windmill nearby, is a brick structure... Its clearly not a WW2 pill-box as the walls are only 3 bricks thick... And it has this configuration inside... Anyone know what it was/was for? I found 2 links on this forum which lead me to believe it was for training purposes in 1940-42.
The county council think it is a WW2 radio direction finding structure the top of Halnaker Hill is a Scheduled Ancient Monument as it is the location of a Neolithic earthwork structure known as a 'causewayed enclosure'. This scheduling includes the WW2 radio direction-finding structure' https://www.westsussex.gov.uk/leisu...laces-to-visit-and-explore/halnaker-windmill/ Also The path to Halnaker Windmill, a magical tunnel of trees The windmill was used as a Home Guard observation post Defence of Britain Archive
Thanks travers1940 See also: https://frontlineulster.co.uk/direction-finding-part-i/ and https://frontlineulster.co.uk/direction-finding-part-ii/ I'm not sure that it makes any sense to preserve this building as it is now. There is no signage to indicate what it was, its currently just a graffiti decorated toilet! There are the remains of a second building a bit lower down the hill which may be related to this structure.
English Heritage say there were four searchlight emplacements on the hill. During World War II, four large searchlights used to seek out raiding enemy aircraft were sited on the hilltop. The searchlight emplacements, the middle two of which are situated within the earlier enclosure, were constructed about 100m apart in a south west facing, semicircular arc. They are octagonal structures about 6m in diameter with concrete foundations and mortar-brick or red brick walls. Apart from the southernmost, which has been largely dismantled and takes the form of a concrete foundation, the emplacements survive to their full height of 2.6m. The northernmost emplacement has been capped with modern concrete and is used as a reservoir. Within the interior are the circular concrete foundation blocks on which the now removed searchlights were mounted. A rectangular concrete platform within the eastern sector of the earlier enclosure would have supported an associated military structure. 1020514 However another theory is put forward by Mike Searle that it is part of a a HFDF or "Huff-Duff" direction finding station. I find this convincing due to the limited space inside the structure to operate a searchlight & this photo of a known HFDF structure at RAF Ibsley. Halnaker Hill WWII RDF station -... © Mike Searle cc-by-sa/2.0 Travers EDIT I now see expanded info but with great pics about what the structure was inside the blast walls in the frontlineulster links you posted.