Translators exploded onto the scene as a way for broadcasters to gain new FM signals on the cheap back in 2003, when some clever religious broadcasters flooded a filing window which resulted in the tendering of thousands of translator-station construction permits. These folks inspired other spectrum-spectulators to jump in, sensing that this would be the last chance to colonize the FM dial in the United States. They all then sold the majority of these permits, for thousands to millions of dollars apiece.
These translators have been mostly utilized to give HD Radio-only programming (like that found on FM HD-2 and -3 subchannels) an analog presence, which some have likened to launching an entirely new station, and to allow AM stations a foothold on the FM dial. Since that first rush, the FCC’s opened multiple opportunities for broadcasters to purchase existing translator stations, most recently as part of FCC Chair Ajit Pai’s vaunted AM revitalization initiative.