Radio is based on the transmission of electromagnetic waves to the atmosphere. These waves travel at the speed of light (300 thousand kilometres per second) and form a specific pattern.
Basically, the radio transmitter converts our voice to electrical signals.
Afterwards, the aerial transmitter converts those signals to electromagnetic waves and broadcasts them into space.
Finally, the radio receptor decodes the waves and sends them back to their original pattern, recovering the information and generating the audio once again.
A radio wave has two main characteristics, frequency and wave length.
According to its function, there are two methods of modulation of radio waves: amplitude modulation (AM) and frequency modulation (FM).
In aviation, radio works with the AM method or amplitude modulation. It uses less bandwidth and is the first one ever used; however, it is also the one which is mostly affected by interference and hence has a poorer audio quality.
FM or frequency modulation is what is used daily when we play the radio in our cars and enjoy the latest hits.
In aviation we do not use all the frequencies for the same purpose:
Communication between longer distances uses other frequencies such as HF.
VHF frequencies propagate in a straight line through the atmosphere but are limited by the line of sight, i.e., the waves do not follow the curvature of the Earth.
This is the reason why It is necessary to install signal repeaters in the surface of our planet
Additionally, pilots can make use of a formula to find out if they are within sufficient range to talk to the station they are contacting.
→ Range in nautical miles = 1.23 x (√h1 + √h2), h1 being the height of the airplane and h2 the height of the station, both expressed in feet.
One Air, three times awarded as the Best Flight School in Spain.
