17,2kHz could be heard by human ear if it was an Audio frequency transmitted by a loudspeaker (at least by young people). However, electromagnetic waves transmitted by huge VLF-antennas, would not be picked uped by the human ear anyhow. For SAQ reception, I Always use a homemade VLF-to-SW RX converter with a ferrite rod as antenna. That works ufb. Best greetings, Regards, DL2GAN.