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13.3.2 VHF Frequency Spread

The frequencies in the part of the VHF band that may be of concern to the pilot

are as follows:

(AM stands for amplitude modulation and FM for frequency modulation)

13.3.3 VHF Frequency Separation
13.3.3.1 Sidebands and Bandwidth

The spread of side frequencies above and below the carrier frequency are known

respectively as the upper and lower sidebands. The total spread of frequencies
in the modulated emission is known as the Bandwidth of the signal. A voice (or

music) transmission consists of many different audio frequencies, up to at least 5

kHz, impressed on the carrier wave. Consequently many side frequencies exist in
the modulated signal, which may have a bandwidth of at least 10 kHz. Such a

signal is classified as an A3E emission; an example is VHF R/T.

13.3.3.2 VHF Bandwidth

The bandwidth is 8.33kHz. For channels separated by 8.33kHz, all 6 digits of the

numerical designator should be used to identify the transmitting channel.
Three digits after the decimal are used for all channels:

118.005 transmitted as ONE ONE EIGHT DECIMAL ZERO ZERO FIVE

Frequencies where the last two digits are zero are transmitted as:
118,000 transmitted as ONE ONE EIGHT DECIMAL ZERO

13.4 VHF Propagation Characteristics

13.4.1 Propagation Paths

The path of a radio wave from a transmitter to a receiver many miles away is not

necessarily direct.

GEN radio 2025 - Midtjysk Flyveskole 99