Azimuthally symmetric (m=0) radio‐frequency (rf) waves for zero and for finite axial wavenumberkare investigated in a low‐compression linear theta pinch. The (k=0) modes occur spontaneously following the implosion phase of the discharge. For thek≠0 modes, a novel 100 MW, 1 MHz current drive is used to excite the plasma column in the vicinity of the lowest fast magnetoacoustic mode at various filling pressures. Phases, amplitudes, and radial mode structure are studied for both thek=0 modes and the externally driven (k≠0) modes. In the first case, the damping is determined from thee‐folding time of the decaying oscillations. In the latter case, the phases and amplitudes indicate a broad resonance structure, from which we extract the damping constant. The energy deposition of the externally driven rf wave leads to a radial expansion of the plasma column, as observed by axial interferometry and by excluded flux measurements. These experimental results are compared with the predictions of two MHD‐like ion‐kinetic models. The characteristic and resonant frequencies, as well as the oscillatory radial mode structure, can be understood within the ideal MHD description. It is found that the viscous kinetic model overestimates the observedk=0 damping by at least an order of magnitude, while both this and the ion Landau‐damping model (with and without ion‐cyclotron effects) underestimate the (k≠0) damping by at least an order of magnitude. The experimentally observed damping and wave‐energy deposition are consistent with the magnitude of the rf oscillations. The efficiency of the rf energy deposition is at least 27%.