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mike-wsm
How can he do spectrum analysis on recorded audio of the noise? VHF is in the MHz, audio capture in the kHz. If its RF noise he should have to connect spectrum analyser on antenna coax. After the radio 'box' everything is 'translated' (modulated?) in audio spectrum. Frequency of noise would be lost, or would be missleading after modulation in audio freq.
Maybe I'm wrong or misunderstood (in that case delete the post)...
If I'm not, alternative solution:
Get an osciloscope from someone having acess to a univ./school lab, they have 50ohm coax input, have it do an FFT on the antenna input of the radio. No idea how you power the osciloscope in the plane though.
Spectrum analysers are usually bulkier than osciloscopes. at least the ones I have access to. Some osciloscopes save the data also in USB sticks for later process.