Why channel names differ from frequencies
European airspace moved from 25 kHz to 8.33 kHz channel spacing to fit more channels into the crowded 118 to 137 MHz band, and all UK aircraft radios have needed 8.33 kHz capability since 2018. Because 8.33 kHz doesn't divide neatly into a display with three decimal places, each channel is given a name. Every 25 kHz block holds one 25 kHz channel and three 8.33 kHz channels. For example, the block starting at 118.000 MHz has:
- 118.000: the 25 kHz channel on 118.0000 MHz
- 118.005: an 8.33 kHz channel, also on 118.0000 MHz
- 118.010: 8.33 kHz on 118.0083 MHz
- 118.015: 8.33 kHz on 118.0167 MHz
So a channel name ending in 0 or 5 is always valid except those ending 20, 45, 70 and 95. On an 8.33 radio you dial the channel name, and the radio works out the frequency and the bandwidth.
Who uses this
Pilots set the channel names published on charts and in the AIP. Scanner and SDR users often need the real frequency, because many receivers tune in kHz steps and show frequencies, not channel names. Set an SDR to the actual frequency with AM mode and a bandwidth of about 6 kHz for 8.33 channels.
Only licensed aircraft and ground stations may transmit on airband. In the UK, the general public isn't authorised to receive aviation traffic either, so this page is a reference for pilots and licensed radio users.
Questions
What frequency is channel 118.005?
118.0000 MHz, the same as the 25 kHz channel 118.000, but with the narrower 8.33 kHz bandwidth.
Which channel names are invalid?
Names ending in 20, 45, 70 or 95, such as 118.020, don't exist in the 8.33 kHz scheme.
Is 8.33 kHz spacing used in the US?
Not for most airspace. The US still uses 25 kHz spacing, so channel names and frequencies are the same there.
Do I need an 8.33 radio in the UK?
Yes. All aircraft radios in UK airspace have needed 8.33 kHz capability since 2018.