A beam ratio technique for microwave observation of S-component sources

The fluctuations in the tropospheric attenuation constitute a major problem when S-component source variations are studied. On records made by means of ‘single beam’ antenna systems, separating solar variations from spurious effects can be very difficult. The twin-beam, beam ratio technique circumvents this problem by deriving a ratio with respect to a reference beam which is identically affected by the tropospheric attenuation and by receiver gain variations.