the spectrum. By comparison with the Type 84 it was massive, a MOPA system with 12 klystron transmitters and 60 receivers. The equipment was housed in the main technical block for the Radar site, the R12 building, the aerial being mounted on top of the building. The Type 85 ended up using the same design of antenna as the T84, although only "one side" of it, the aerial for the associated secondary radar being mounted underneath, rather than above. The Type 85, however, offered an extremely advanced ECCM system enabling the shifting frequencies on the fly, or as it is now known frequency agility. The radar had 12 transmitters which were grouped in four bands, A, B, D & E. Each transmitter had a peak power output of 5 MW, giving 60 MW total power output, this massive power was routed through waveguide switches that enabled the aerial to produce a standard "cosec squared" beam or, in conditions of intense ECM the power concentrated into a beam 6 degrees high aimed at the target. As well as the frequency agility and sheer power the Type 85 had multiple receivers enabling the return signals to be detected through the heaviest jamming, this included "dicky fix" receivers to combat carcinotron jamming. Post reception processing, including double integration loops enabling the comparison and discarding of spurious returns enhanced the ECCM capability still further. Whilst not having the Moving Target Indicator (MTI) facility the Type 84 had, the frequency band and processing ensured the Type 85 produced a clear picture even under the most arduous conditions. As the transmission and reception of the Type 85 was based on 12 beams it was also a 3D radar. Data from the radar was passed to the Automatic Height Finder which compared comparative strength of returns from a target between beams. Given the range and known angle it is a simple process to calculate height. However this was being done hundreds of times a second on multiple targets, in the late 1960s and early 1970s it was a considerable feat. Secondary radar The secondary radar used in the system was the Cossor SSR750. Each primary radar had an associated secondary radar, at RAF Staxton Wold and RAF Neatishead there was an additional "freestanding" SSR. Secondary Radar information was associated with the primary (search) radar and presented on the same display. This gave operators a range of information