Spectra, dimensions and luminosities of radio sources in the Culgoora-3 list.

About 2000 spectra of radio sources in the Culgoora-3 list are analyzed. Each spectrum is fitted with a first-degree polynomial, and an attempt is made to define the second and third-degree curvatures in various groups of identified sources. The distributions of spectral index for various classes of optical identification are given, and the intrinsic luminosities of Culgoora-3 sources which have been identified with various classes of optical object with measured redshift are discussed. The results of fitting elliptical Gaussian brightness distributions to the 163 Culgoora-3 maps is described, and an analysis of the barely resolved sources is presented. The results of examining the optical fields of 59 previously unidentified Culgoora-3 sources are given. The overall results indicate that QSOs differ from radio galaxies in having a distribution of linear spectral indices with a pronounced tail towards the low values of spectral index.