Nuclear weapons tests in Australia known at the time as Christmas Island (not to be confused with Christmas Island in the Indian Ocean) between 1957 and 1958. These were airbursts mostly occurring over water or suspended a few hundred metres above the ground by balloon. In Australia there were three sites. Testing was carried out between 1952 and 1957 and was mostly done at the surface. A few hundred smaller scale tests were conducted at both Emu Field and Maralinga between 1953 and 1963. Two separate atomic test projects occurred at the islands, the first being Operation Hurricane and the second being Operation Mosaic The
Radar, Anti-Aircraft No. 3 Mk. 7 ten years off suggested no major production should take place, as developments in the interim would render any radars built in that period obsolete. However, various events in 1949, notably the first Soviet atomic test, led to sweeping upgrades, including the first contract for production Mk. 7's. These began to arrive in 1952. The Swiss Air Force received twelve Mk. 7's in 1958, which they referred to as Feuerleitradar ("fire control radar") Mark VII. They combined them with their own predictor, the Hasler-built "Kommandogerät" ("command device") 43/50R. Like its British counterpart, the 43/50R could be fed information directly from the