[en] Effect of magnetic field within zero value range on SHF power absorption in XBa₂Cu₃O₇-type superconducting ceramics where X=Y, Eu, Yb was investigated. Experiments were conducted at SHF power different levels with more thorough investigaition of signal behaviour. It was determined that in this case it is possible to detect absorption intensive narrow reverse signal. Spectrometer with EPR-tomograph adapter was used in the experiments. Possibility to detect narrow intensive signal allows to use it in heterogeneous magnetic field in case of nondestructive investigation of distribution of superconductive phase over specimen volume. It enables to acquire valid information concerning spatial distribution of properties (at least the values of the first critical field) in essentially heterogeneous substances to which high-temperature cermaics belong