Channel spacing in the airband has been 25 kHz. However, increasing congestion has led to further subdivision into 8.33 kHz channels.

In general:

• 8.33khz spacing: increase by 0.005 Mhz → 118.0333 MHz, but selects 118.035
• 25 khz spacing: increase by 0.025Mhz

Caution must be exercised with respect to the indication of transmitting channels in VHF radiotelephony communications when five digits of the numerical designator are used in airspace where aircraft are also operated with channel separation capabilities of 8.33/25 kHz. On aircraft installations with a channel separation capability of 8.33 kHz and more, it is possible to select six digits on the radio management panel. It should therefore be ensured that the fifth and sixth digits are set to 25 kHz channels.