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Parts of this article were originally published in sections starting in December 1993 when I was writing for the club newsletter. Although I do not profess to be an expert on radios, I do have a basic understanding of their operation. This basic understanding has helped me in analyzing problems in the past and may do the same for you.
Reprint of this article is only allowed with my easily obtained permission - Al Coelho
The use of Radio Control in our hobby has advanced drastically since its use in the 40's, to our present day systems. Original systems only transmitted a carrier wave signal, which when detected activated an electromechanical device know as an escapement. These escapements were rubber band powered and the systems were basically single channel operation.
Refinements to the systems transmission included the use of superheterodyne receivers and tone modulated transmission. The galloping ghost system with its motor driven, constantly wagging, tail was the first proportional system. And the reed systems with their vibration sensitive reed banks were our first multi channel units. All of these systems are antiquated by today's standards and most would not even work in our current overcrowded radio environment.
The digital proportional control system we use today emerged in the 60's. The "Digitrio", a 3 channel system designed by Ed Thompson, was originally a construction project in Radio Controlled Modeler magazine. World Engines began kitting the design in 1966 and the digital evolution began. Although much refinement to the components has been done, the basic design is still what is used in today's modern PPM systems.
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