Aircraft Communications Interference Tests.
Final rept. Apr-May 75.
NATIONAL AVIATION FACILITIES EXPERIMENTAL CENTER ATLANTIC CITY N J
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This report covers tests conducted to determine the possible causes of interference to aircraft very high frequency vhf voice communications resulting from transmissions from the vhf digital data link system operating onboard the same aircraft. Tests were conducted to determine aircraft vhf antenna isolation and vhf receiver response. The tests show that isolation depends on the physical positioning of the antennas on the airframe and that existing isolation found to be as little as 23 dB can realistically cause interference or quieting between transceivers even though they are operating at different frequencies up to 4 MHz apart. It was also found that transceiver design affects the rejection of undesired received signals. It was recommended that maximum isolation be maintained between aircraft antennas, receiver design be optimized for rejection of undesired signals, and cockpit communications discipline be used. Author
- Voice Communications