Abstract: According to facts that the range extension of the echo due to the influence of the aspect sensitivity in the detection of coherent scattering radar, this paper studies the dependence of the echo range extension and radar frequency are affected by the scales of the irregularities. Based on the coherent scattering radar echo equation, the echo broadening with the scales of the irregularities is calculated, and the simulation of the dependence of the radar operating frequency and the range extension is carried out, the variation of the fitting slope of the radar operating frequency and the broadening width with the scales of the irregularities is obtained. The results show that there is a linear correlation between the echo broadening width and the radar frequency, and there is the only correspondence between the fitting slope and the longitudinal scale of the irregularities. The slope calculated by linear regression can be used to reverse the scale of the irregularities. Since the calculation of slope does not require the acquisition of absolute radar antenna gain, feeder loss and transmission power, it can provide a new scale detection method of the irregularities for non-calibration VHF radar. The result is of significance for the development of new detection techniques for the irregularities.