A study of the panchromatic properties of radio sources makes it possible to research the evolution of active galactic nuclei and their relationship with the environment. The study was made of a complete sample of radio sources in terms of flux density from surveys of the "Cold Experiment", carried out on the RATAN-600 radio telescope at a frequency of 3.94 GHz in 1980–2000. We have found hosts for 95\% of these radio sources. According to the radio luminosity estimates, most of the sources are powerful FRII type radio sources. Based on photometric data and color indices among the hosts we have identified groups of quasars, early-type galaxies, and late-type galaxies. Additionally, the late-type galaxies are subdivided into a smaller group with a relatively low radio loudness index and a larger group with a high index.

Depending on the radio luminosity, the sources were divided into groups. In each group, the median of the ratio of the absolute magnitude to the radio luminosity was calculated, and the number of quasars and the number of galaxies were also calculated. Correlations are found whose behavior can be explained by a change in the screening properties of the torus. As the radio luminosity increases, the shielding properties of the torus decrease.

Long-term variability was found with varying degrees of confidence in 18\% of the radio sources. The hosts of these sources with magnitude R$\leq$18$^m$ exhibit variability in the optical range as well.

According to the multi-frequency maps of the Planck mission, for 70\% of the sources of the RCR catalog, at a level $\lesssim$4$\sigma$, a positive signal was found at least at one frequency. The spectral studies confirm the connection of these positive spots with the radio sources.
To search for the Sunyaev-Zel'dovich (SZ) effect, the studies of the properties of "hot" and "cold" spots near sources were carried out. 16\% of the radio sources have signs of the SZ-effect at level $\lesssim$4$\sigma$. One fifth of them are in the catalogs of galaxy clusters, which confirms the applicability of our technique for searching for the effect in faint sources.