Milli-arcsecond structure of a complete sample of radio sources. I. VLBI maps of seven sources

The sample of 51 sources between declinations 350 and 700 with galactic latitude >100 and flux density > or =1.3 Jy at 5 GHz contains 36 objects that are suitable for study by very long baseline interferometry (VLBI). Observations have been made of seven of these with a VLBI array of four U.S.A. antennas at a frequency of 5 GHz with full hour-angle coverage. The results show a wide variety of morphologies: two sources (0133+476 and 0859+470) are only slightly resolved, one is a double source (0923+392 = 4C 39.25) with a constant separation, three (1807+698 = 3C 371, 1828+487 = 3C 380, and 2200+420 = BL Lac) have an elongated linear structure, and the last (0316+413 = 3C 84) is complex. Later papers in the series will present the observations of the remaining sources in the sample