Spatial (aperture) noise generators

Spatial noise generators with apertures of 200 mm, 270 mm, 1500 mm were developed in OKB MEI. Spatial noise generators with apertures of 200, 270 mm are Djuar vessels filled up by boiling liquid nitrogen, with metal cylinder, fixed in liquid nitrogen´s zone. One of cylinder´s founding is cooled by boiling nitrogen. It is covered by radio-absorption material. Another founding, covered by heat protection radio-transparent material, is radiating aperture of spatial noise generator. Spatial noise generators with aperture of 1500 mm is a collimating system, which consists of the parabolic reflector (part of parabolic) and radiator, which consists of aperture noise generator and additional reflector (contra-reflector). Additional reflector also provides lighting of main mirror (parabolic reflector) and forming of plane parallel collimation beam. Methodology of noise temperature unevenness measurements in the section of the collimation beam is presented.