FM radio simulcasting - A systems approach

The past several years the technique of simulcasting (the use of multiple transmitters simultaneously transmitting the same information) has become necessary to satisfy the geographical coverage requirements of large RF transmission systems. It has been found that specially designed equipment is needed to adhere to the stringent requirements of this type of system in order to obtain usable overlap area coverage. It has also been found that a properly designed simulcast RF transmission system has many advantages over a single transmitter even within the same coverage area. In order to develop system design guidelines a set of laboratory tests were devised to determine the parameters required for an acceptable system. A system audio processing scheme was then devised that would implement the system and conform to the design guidelines obtained from the laboratory tests. In this paper I will describe these laboratory tests and show the results. The audio processing scheme that was then used is described as well as several other system design considerations. Lastly, the advantages of implementing a transmission system using simulcasting techniques is discussed.