Long-Range Infra-Red Transmitter-Receiver

EE 36 November 1987 LONG-RANGE INFRA-RED TRANSMITTER-RECEIVER by J C Stekelenburg This two-way, infra-red, FM, communication system covers line-of- sight paths of remarkable lengths without the use of expensive optoelectronic devices. There are many who are con- vinced that infra-red compo- nents are only useful for remote control systems with a range of 10 metres or so. Powerful IR emitters are well out of the financial reach of the average home constructor, and their usefulness is often rightly queried simply because doub- ling the radiated power hardly increases the effective transmit- ter range. Notwithstanding the latest achievements in op- toelectronic technology, the real key to long-distance com- munication in the infra-red part of the frequency spectrum is a well-known physical phenom- enon: beam convergence. Principles of telecommunication Telecommunications engineers use calculated, i.e., hypotheti- cal, models to assess and study the technical feasibility of point-to-p...