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 5360 kHz. 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 bandwidth of typical SSB transceivers.