[en] Results of calculations and experimental researches of resonance systems of test and basic samples of a compact isochronous cyclotron (CIC) with the 103 cm-in-diameter poles are presented. The CIC is intended for applied purposes. The CIC basic sample is intended for acceleration of protons, deuterons, α-particles and helium 3 ions with beam intensity of the order of 50-300 μA in the energy range from 5 to 26 MeV. The radiotechnical resonance CIC system consists of two quarter-wave resonators joined by an interdee capacitor and excited in opposite phases from the end cascades of RF generators. The resonance system frequency is changed with the help of movable panels and pre-set capacitors. The following conclusions are made on the basis of the experimental results: the design of the resonance system is simple and reliable in operation, the design parameters are close to the experimental ones