Ear potential that is transmitted along the spiral ganglion, which sends information through the auditory portion of the vestibulocochlear nerve to the temporal lobe of the brain. The human ear can generally hear sounds with frequencies between 20 Hz and 20 kHz (the audio range). Sounds outside this range are considered infrasound (below 20 Hz) or ultrasound (above 20 kHz) Although hearing requires an intact and functioning auditory portion of the central nervous system as well as a working ear, human deafness (extreme insensitivity to sound) most commonly occurs because of abnormalities of the inner ear, rather than in the nerves
60-meter band bandplan strongly recommends that the WRC-15 frequencies should only be used if other 5 MHz frequencies, allocated under Article 4.4, are not available. It does not require stations to adopt the USB dial frequencies of 5354, 5357, 5360 and 5363 kHz but these frequencies provide a good fit with the American channel on 5357 kHz, and UK stations which can use 5354 and 5363 kHz (but not the middle two). Also, it is only by using these exact frequencies that there will be enough room for four simultaneous SSB conversations without mutual interference, assuming the 2.8 kHz "de facto" standard