Abstract: There is provided a mechanism for signalling interference protection comprising: transmitting, along with adjacent channel frequencies, an odd/even bit associated with odd/even channels that differentiates adjacent channel frequencies from one another, receiving transmitted an odd/even bit associated with odd/even channels that differentiates adjacent channel frequencies from one another, and responding to one(s) of interest while remaining unresponsive to other than that of interest.

Abstract: An apparatus for limiting shadowing of RF coverage areas around antennas and closely associated equipment housings is disclosed. The equipment housing and antenna are located in close proximately such that the RF coverage area of the antenna is partially shadowed due to signal blockage by a face of the equipment housing or other structure. The shadowed RF coverage area is eliminated or substantially reduced by placement of a reflector to reflect emitted signals from the antenna into the shadowed RF coverage area.

Abstract: The present invention provides a system for simulcasting and diversely receiving radio frequency (RF) signals. The system of the present invention comprises at least one RF transceiver and a plurality of RF units each including a transmitter for simulcasting an RF signal to a user and further including one receiver which is paired with another receiver in another one of the RF units, the pair of receivers providing for diversity reception of an RF signal from the user. The implementation of diversity reception with only one instead of two receivers in each RF unit, as taught by the present invention, reduces both signal loss and required cabling in the system.

Abstract: A system for facilitating link continuity and prompt supervisory control in a communication system with discontinuous transmissions comprising varying the carrier power in a first communication unit and varying frequency deviation of a modulating signal to provide a continuous signal detectable by a second communication unit, where continuous monitoring at the second communication unit allows for rapid detection and reaction to received supervisory control signals through the use of continually comparing the received supervisory signal to an expected signal and qualifier signal to enhance the reaction time of the second communication unit.

Abstract: Transmitter combining apparatus includes up to five RF filters (100) coupled to a microstrip combiner (300) for combining up to five input signals for application to a common antenna. The RF filter (100) includes a ceramic resonator (116) sandwiched between first and second compensating discs (114 and 120) and first and second shield plates (142 and 148) for temperature compensation, low loss mounting and heat sinking of the ceramic resonator (116). Good thermal contact between the ceramic resonator (116), discs (114 and 120) and shield plates (142 and 148) is produced by a compressive force exerted by springs (144-147) of shield plate (142) when the top cover (112) is attached to the aluminum housing (124). The resonant frequency of the RF filter is tuned by means of an aluminum tuning shaft (102) and ceramic tuning core (118) which are positioned by brass bushing (133) in top cover (112).