We consider the ionospheric models that are suitable for over-the-horizon HF and UHF band radars. Namely, there are three such models: the numerical model developed by IZMIRAN and Fedorov Institute of Applied Geophysics, the numerical model designed by ISTP SB RAS and IDG RAS, and the probabilistic model worked out by IDG RAS. We briefly describe these models and report the results of the analysis of their compliance with radar requirements. Probabilistic models are shown to be most promising; hence, they must be placed at the frontier of ionosphere simulation.