The radar equipment arrived on the island on 5 Jan 40, accompanied by Sub Lt Irvine and the first batch of naval ratings to man the radars were drafted in with Sub Lt Feachem on 23 Jan 40. The photo below, from the collection of the late Lt Dunworth, shows the assembly of the Transmitter aerial at AES2. The first radar (AES3) became operational on 23 Feb and AES2 followed a few days later. AES3 was sometimes known as Fair Isle South and AES2 as Fair Isle North.
Throughout Feachems' tour both AES2 and AES3 operated with the original type of Chain Home Low equipment, ie, separate Transmitting and a Receiving Aerials at each site. It was only after Mar 42 that both sites were each converted to single aerial operation.
During the first week of May there was a visit by representatives from various organisations including, 70 Wing, 71 Wing, 60 Group and theTelecommunications Research Establishment (based at Worth Matravers in Dorset at the time). The visitors were there to look at the re-siting of the Unit to Compass Head, about a mile north of Sumburgh Head. The Sumburgh site, next to the lighthouse, had a number of problems. The lighthouse tower, other buildings and the foghorn caused some oscuration to the radar signal, whilst the Transmitter and Receiver aerials had been positioned too close to each other for maximum efficiency.
Three more photos of the AES6 buildings, which were taken recently, follow and are used (with permission) from this excellent site: http://www.anti-aircraft.co.uk/