Abstract: Systems, methods, and computer-program products for communicating auditory alerts about runway hazards to aircraft. A conflict on at least one arrival runway is identified using information received from an existing conflict detection system. An auditory alert associated with the conflict is generated and then modulated onto a carrier frequency. The carrier frequency may be a 75 MHz marker beacon carrier frequency, and further, the carrier frequency may be slightly offset from the 75 MHz marker beacon carrier frequency. The modulated alert is transmitted to an aircraft approaching the arrival runway through a directional antenna, which receives the transmitted auditory alert through a marker beacon receiver without requiring additional flight deck equipment. The transmitted alert does not interfere with transmissions from both an outer marker beacon associated with the arrival runway and marker beacons associated with adjacent runways due to transmitted power levels and antenna directivity.

Abstract: Systems, methods, and computer-program products for communicating auditory alerts about runway hazards to aircraft. A conflict on at least one arrival runway is identified using information received from an existing conflict detection system. An auditory alert associated with the conflict is generated and then modulated onto a carrier frequency. The carrier frequency may be a 75 MHz marker beacon carrier frequency, and further, the carrier frequency may be slightly offset from the 75 MHz marker beacon carrier frequency. The modulated alert is transmitted to an aircraft approaching the arrival runway through a directional antenna, which receives the transmitted auditory alert through a marker beacon receiver without requiring additional flight deck equipment. The transmitted alert does not interfere with transmissions from both an outer marker beacon associated with the arrival runway and marker beacons associated with adjacent runways due to transmitted power levels and antenna directivity.

Abstract: A CLIMAX-network-compatible receiver with squelch capability comprises a demodulator for processing RF and IF, a squelch gate in the intelligence processing channel, and squelch gate control circuitry connected between the demodulator IF (or demodulator RF) and the squelch gate. In the control circuitry, a swept band (i.e., swept frequency) type of spectrum analyzer receives the demodulator IF and outputs a waveform whose envelope represents all the frequency components in the tested IF band. The detected envelope of the analyzer output is next treated by a compression-effecting log amplifier whose output is then tested by two different detectors for carrier attributable content and noise attributable content. The outputs of the two detectors are differenced and such difference is used to control the gate. The log amp ensures that the gate is controlled in accordance with the ratio of IF carrier to IF noise, regardless of whether IF gain variations change the difference between IF carrier and IF noise levels.