To study physical and morphological characteristics of distant quasars we carry out radio-optical investigation of 30 quasars from the Cambridge 7C catalogue second area (0.097 square radians). All these objects have angular sizes less than 1 arcsec on 102 MHz images. Average values of absolute magnitudes and spectral indices have been calculated for them (M = −26.51 ± 0.25, a = 0.66±0.25). It was shown that 60% of compact radio sources from the FIRST catalogue (1400 MHz) are candidates of distant quasars.