An agricultural combine has a variable displacement pump connected to four drive motors that drive four wheels. A lock lever is provided with access forwardly of the head rail that automatically locks the head rail in position on the mounting bracket and conditions the mounting bracket for manual release of the headrail. A purlin assembly has first and second purlin members that are rotatably coupled about a purlin mid-joint. This is followed by analysis to determine asbestos concentration. A distribution matrix processor substitutes the differentially coded STBC into a distribution matrix preset according to the number of transmit antennas, and outputs the differential STBC code of the distribution matrix to the transmit antennas. A personal identification method is also disclosed.