Evolution of low-frequency contribution in emission of steep-spectrum
  radio sources
  We consider evolution properties of galaxies and quasars with steep radio
spectrum at the decametre band from the UTR-2 catalogue. The ratios of source's
monochromatic luminosities at the decametre and high-frequency bands display
the dependence on the redshift, linear size, characteristic age of examined
objects. At that, the mean values of corresponding ratios for considered
galaxies and quasars have enough close quantities, testifying on the unified
model of sources. We analyse obtained relations for two types of steep-spectrum
sources (with linear steep spectrum (S) and low-frequency steepness after a
break (C+)) from the UTR-2 catalogue.
