As an aircraft flies overhead, it receives radio signals in a 360 degrees circle around the aircraft. So these radio stations must be placed into a database, which contains the address of the main Db. This database must be updated every fifteen minutes or so, for an aircraft doing 100mph. The following things will happen if the selected frequency is in the range:
The Morse Code is basically a tone generator (Arduino). The values that you need for your fist are dot length, dash length, and character inter-spacing and word inter-spacing as every fist is different. Our word inter-spacing as the call is repeated every so often per minute.
The audio output will be handled by an integrated amp as I will only need a few watts, at best.
Normally this system has 5 parts: