9C: a survey of radio sources at 15 GHz with the Ryle Telescope

The fields chosen for the first observations of the cosmic microwave background with the Very Small Array have been surveyed with the Ryle Telescope at 15 GHz. We have covered three regions around RA 00(h) 20(m) Dec. +30degrees, RA 09(h) 40(m) Dec. +32degrees and RA 15(h) 40(m) Dec. +43degrees (J2000.0), an area of 520 deg(2). There are 465 sources above the current completeness limit of approximate to25 mJy, although a total of approximate to760 sources have been detected, some as faint as 10 mJy. This paper describes our techniques for observation and data analysis; it also includes source counts and some discussion of spectra and variability. Preliminary source lists are presented.