Abstract

1. Structure of the URAN network:
   • Geographical location of the URAN antennas
   • UV-coverage and synthesized beam
   • Antennas and facility (beam control, time and frequency synchronization, data storage)
   • Main parameters of the interferometers (frequency range, angular resolution, sensitivity etc.)
2. Interferences and distortions at decameter wavelengths:
   • Broadcasting interferences
   • Interstellar medium (restriction of an angular resolution, radio wave absorption)
   • Interplanetary plasma (a range of suitable elongations)
   • Ionosphere (amplitude and phase scintillations, integration time restriction)
3. Methods of observations and data reduction.
4. Some results of radio sources studying at the decameter wavelengths:
   • Galactic radio sources:
     • Low frequency compact radio sources associated with pulsars in supernova remnants and interstellar scattering (3C144, 4C21.53);
     • Angular structure of the Cas A
   • Extragalactic radio sources:
     • Structure of the radio galaxies 3C338, 3C111, 3C234 (lobes, hot spots, cores)
     • The quasars 3C196, 3C154, 3C216 at low frequencies (self-absorption, extended components with steep spectra);
     • Cosmic plasma and structure of the radio sources at decameter wavelengths