Abstract-The effect of land cover is incorporated in the radio propagation prediction algorithm of Q-Rap. It is implemented by optimizing both the effective height of the land cover, hence affecting obstruction-loss calculations, and by the addition of terms to the basic transmission loss algorithm. A complete set of separate coefficients to these terms are determined for each land cover type. The optimization method improves the standard deviation of the error from 9.6 dB to 6.3 dB for measurements and predictions done at 390 MHz. This is an improvement of 3.3 dB over the original model that comprise of the free space loss equation with obstruction loss calculations for multiple knife edges. At this frequency the correlation coefficient between the measured and predicted values improved from 79.5% to 85.6%. At 2145 MHz the optimization method improves the standard deviation of the error from 16.2 dB to 8.6 dB and the correlation coefficient between the measurements and predicted values from 56.2% to 70.5%. The use of the correlation coefficient between the measured and predicted signal values in addition to the standard deviation of the error and mean error as criteria to be used when evaluating propagation prediction models is also proposed in this paper. A basis for best practices in the tuning of propagation prediction algorithms in radio planning tools using semi-empirical models is presented.Index Terms-open source radio planning tool, Q-Rap, radiowave propagation, radio propagation model tuning, radio propagation terrain factors, radio systems planning, UHF propagation..