The radio altimeter test set system can be coupled to the altimeter directly through the latter’s Tx/Rx ports or by using the supplied antenna couplers, which accommodate most aircraft. RF looped tests verify Tx frequency, power, and sweep rate, while the RF-level control permits testing UUT sensitivity. The unit can simulate altitude from –100 to 50,000 ft with ±1.5-ft accuracy, be programmed with multileg climb / descend profiles, and be connected to up to two other test sets for coordinated two- or three-channel simulation.