Abstract: A method, apparatus and circuit for testing a radio altimeter is disclosed. During the test-mode operation of the altimeter, a signal processor controls a transmitter to generate a radio frequency signal at a first period of time, which is transmitted through an attenuator, transmitted then through a receiver and received by the signal processor at a second period of time for processing of altimeter operational information.

Abstract: An apparatus according to various aspects of the present invention is configured to collect and/or emit electromagnetic waves, particularly microwaves. In one embodiment, a transducer system includes an integrated waveguide, transducer, and processing circuit. The processing circuit is disposed between two plates which also serve to define the waveguide. The transducer, such as an E-field probe, is disposed in the waveguide to collect or emit electromagnetic waves such as microwaves. The transducer is directly connected to the processing circuit within the integrated unit.

Abstract: A Traffic Alert and Collision Avoidance System(TCAS) antenna is mounted on a selected forward portion of an aircraft thereby extending the effective forward range of the TCAS. The antenna and ground plane are tilted relative to conventional TCAS antennas thereby aligning a peak of the antenna's radiation pattern along the aircraft's level line of flight. The resulting increased gain directed forward of the aircraft increases the forward range of the TCAS for both receiving and transmitting TCAS signals. The invention is also useful to extend the range of other aircraft systems including transponders. Alternate embodiments include tilting a conventional TCAS antenna mounted on a middle portion of the aircraft.