The 6C survey of radio sources - II. The zone 30 <delta<51, 08h30m <alpha<17h30m.

The 6th Cambridge survey of radio sources covers most of the sky north of δ+30^deg^ with an angular resolution of 4.2 x 4.2 cosec δ arcmin^2^ and reaches a limiting flux density of 190 mJy at 151 MHz in the present zone. In this paper the methods used to produce the survey maps from a non-tracking telescope operating at declinations other than the north celestial pole are described: this forms the basis for all future papers in the series. Maps of a high galactic latitude region 30^deg^ <δ <51^deg^, 08^h^30^m^< α<17^h^30^m^ are presented, together with a list of 8278 sources in the 2030^deg^^2^ covered. A source count over the range 200 mJy <S(151)<100 mJy is derived.