Variability of extragalactic sources at 2.7 GHz. I - Results of a 2-yr monitoring program

Three hundred sixty-five extragalactic sources selected without strong spectral bias have been monitored for variability at 2.7 GHz between September 1972 and August 1974 using the NRAO 300-ft transit telescope. This paper (the first of a series of three) describes the observing and calibration procedures which permit flux-density measurements with an internal consistency of order 1 %. Table II presents the results of this monitoring program and Table III gives flux densities for 41 sources for which observations indicating variability have not previously been published. The astronomical implications of the results are discussed in Paper III of this series.