Western Electric, the equipment supplier for AT&T, was also a major supplier of equipment to radio stations in the 1920s, '30s & '40s. This transmitter at WMMN in Fairmont, WV in 1940 was among the first to use the new Doherty modulation system which was at the time the most efficient known. It was also W.E.'s first 5 kw transmitter to be totally air cooled. Prior to this transmitters in the power class used water-cooled tubes in the output stage.