The Rounded Obstacle model is based on Section 7 (“Diffraction Over a Single Isolated Obstacle”) of Tech Note 101(Transmission Loss Predictions for Tropospheric Communication Circuit, 1967, NTIS), treating path obstructions as rounded obstacles as described in Section 7.2. In addition, methods from Section 9 (“Forward Scatter”) are used to compute tropospheric scatter losses. The two loss components may be combined in any of several user-selected methods. Some of the source code for the model was adapted from the program QZGBT used for protecting the RF noise floor at the National Radio Astronomy Observatory (Green Bank, WV) radio astronomy site.
