Pass parameters and execute Splat! to calculate propagation loss over irregular terrain

function SPLAT_PL creates transmitter and receiver sites defined in TX and RX, respectively, then executes the SPLAT! code to calculate the path loss (in dB) between the transmitter and receiver sites, and reads the resultant data files created by Splat!.
SPLAT! is an RF Signal Propagation, Loss, And Terrain analysis tool for the electromagnetic spectrum between 20 MHz and 20 GHz.
SPLAT! (http://www.qsl.net/kd2bd/splat.html and GUI at http://www.ve3ncq.ca/wordpress/?page_id=62) provides site engineering data such as the great circle distances and bearings between sites, antenna elevation angles (uptilt), depression angles (downtilt), antenna height above mean sea level, antenna height above average terrain, bearings and distances to known obstructions based on U.S. Geological Survey and Space Shuttle Radar Topography Mission elevation data, path loss and field strength based on the Longley-Rice Irregular Terrain as well as the new Irregular Terrain With Obstructions (ITWOM v3.0) model, and minimum antenna height requirements needed to establish line-of-sight communication paths and Fresnel Zone clearances absent of obstructions due to terrain.