University of california at Santa Barbara Anisotropy Program: degree scale results from the South Pole 1990-1991.

We report on the preliminary result of a search for anisotropy in the cosmic background radiation (CBR). Our receiver operates with four equally spaced channels from 25 to 35 GHz with a beam size of approximately 1.5 degrees full width at half maximum. The system operated successfully for 500 hr at the South Pole during 1990-1991 austral summer. The data from one region, representing 25 hr after editing, are presented here. A strong signal is present in the lower-frequency channels with a spectrum unlike CBR fluctuations. The highest-frequency channel has the smallest contribution from this signal and has been used to set a 95% confidence level upper limit DeltaT/T </= 1.4 10-5.