SELCAL operates on the high frequency (HF) or very high frequency (VHF) radio frequency bands used for aircraft communications. HF radio often has extremely high levels of background noise and can be difficult or distracting to listen to for long periods of time.
SELCAL functions on the high frequency (HF) or very high frequency (VHF) radio bands used for aircraft communications. HF radio often has extremely high levels of background noise and can be difficult or distracting to listen to for extended periods of time.