The purposes of a translator district shall be to serve the public interest, convenience, and necessity in the construction, maintenance and operation of translator stations and any system necessary thereto by appropriate electronic means for television program distribution, but the purposes are not meant to include the construction or operation of community antenna systems, commonly known and referred to as cable TV systems. Translator districts organized prior to January 1, 1977, may, in addition to other powers conferred by this chapter, receive and broadcast FM radio signals by appropriate electronic means.