A method of fast non-destructive absolute spin monitoring for a bunched beam in an accelerator ring based on use of the RF techniques is considered. The coherent spin of the beam is driven by RF magnets in the spin echo regime. A passive superconducting resonator is proposed to respond to the flipping spin. A possibility is established to enhance the spin-related excitation of the resonator using the charge-resonator dipole interaction and spin-orbit coupling induced by the quadrupoles. It is shown that the spin impedance can be gauged via measurements of the beam dipole impedance. The noise demands are evaluated. Numerical examples are given.