[en] The results of experimental investigations of the emission spectrum characteristics at axial and planar channeling of 2 and 3.5 GeV electrons on a 1 mm-thick diamond crystal are presented. The specifications of the experimental set-up, the logics of data gathering and processing are also given. It follows from the experimental data, that the emission intensity under the peak, in the energy range from 25 to 220 MeV at an axial channeling of 2 GeV electrons is about 2.6 times lower than in the case with 4.5 GeV electrons. The characteristic emission frequencies differ by about 5 times, the intensity at the peak -about 1.6 times. 4 refs.; 4 figs.; 1 tab