This paper reports on some consequences of a comparison between model calculations of the S-component solar radio emission and observations of active regions at different wavelengths in the microwave range. Calculations of the transfer of the Scomponent emission were carried out on the base of horizontally averaged semi-empiricalv models of the solar atmosphere above sunspots and plage regions consistent with optical and EUV observations and account for Coulomb bremsstrahlung and gyromagnetic emission in dipole-like or
force-free extrapolated magnetic field configurations,
While the mean characteristics are quite in accordance, discrepancies between observations and calculation arise mainly with respect to fine structures, Considering such discrepancies, (i) possible reasons for an obvious lack of observed ring structures of S-component sources above sunspots are discussed. (ii) Subtelescopic fine structures in plage regions are predicted whereas bright plage elemente are assuraed to be embedded in a quasi-quiet background. (iii) Different kinds of loop emissions are considered, among them strange cases of persistent "hot" loop emission connected with emerging magnetic flux regions.
Based on observations of the extraordinary behind-limb flare on February 16, 1984 the radio-flux time profiles at different
dm-wavelengths and dynamic spectrum corresponding
to a source height z > 200000 km above the photosphere are
compared with hard X-ray observations reported by Kane et al.
(1987). The nature of the dm-emission and implications on the
flare process are discussed. Dependíng on the emission
process estimations of relevant plasma parameters (electron
density, magnetic field) are given.