Page 85 - Radio BEG-engelsk- engelsk tekst

© Henning Bach Andersen

A1A signals cannot be heard unless the receiving equipment is equipped with a

BFO, which is a special device that puts sound on where there is no carrier wave.

11.2.3 Low frequency tone

Inventive people figured out how to

transmit audible tones.

You modulate the amplitude height
of the carrier wave with the low-
Low frequency tone
frequency tone.

This is called amplitude modulation (AM).

The audible tones have a lower frequency than the carrier wave.

11.2.4 A3E

A3E is the name of this waveform. It is not far from modulating the amplitude

with an audible tone to modulating it with speech.

All that is required is a microphone.

This is what the waves sent from our aircraft radio

look like.

11.2.5 F3E / FM

This way of modulating is called frequency modulation (FM).

Here the amplitude is constant, but the

frequency changes.

These waves are called F3E and they are used in vehicle communication.

BEG-english radio marts 2026 - Midtjysk Flyveskole 85