VHF Interference Measurements on Cable Harnesses in Passenger Cabins of Airplanes

This paper deals with the investigation of interference coupling and transmission characteristics within the frequency range of very high frequency (VHF) voice transmission and navigation systems in airplanes. Possible measuring methods are analyzed for their applicability in the determination of transfer functions. It is revealed that, due to the complex harness with many crosspoints and junctions, a separation of cable- and field-coupled VHF interference is neither useful nor possible. Radiation coupling between the cable harness and the inner fuselage volume is not only important but also turns out to be the dominating mechanism for the description of electromagnetic compatibility transfer characteristics in the VHF frequency range.