Microwave diagnostics of the Chilbolton 25M antenna using the OTS satellite

It is pointed out that reflector shape measurement at normal working elevation angles is of prime importance in achieving performance optimization. New developments of this technique are reported as applied to a 25-m-diameter reflector using a geostationary satellite to provide a far-field source at a typical operational elevation angle. The satellite used for these measurements appears at a mean elevation angle of 30.5 degrees from Chilbolton (U.K.). A 2.4-m-diameter paraboloid antenna is used to provide a phase reference signal for the receiving system and is situated in close proximity to the 25-m antenna to minimize phase measurement errors deriving from tropospheric disturbances. The results are shown to validate the microwave metrology approach for determining the reflector profiles using a satellite source.