The basic parameters for the spherical two-reflector antenna are set forth. This antenna operates in the millimeter and centimeter ranges and the main fixed reflector has a diameter of about 5 m. A justification is given for the selection of the parameters and data are presented on the design and construction. Information is given on the spatial orientation, the automatic control system, and the radiometer. Certain results are given of the experimental investigation of the antenna and of temperature measurements of the sun and moon at a wavelength of 8 mm.