..frequency doubled, minus the other station, then add...my head hurts!
There are stories around the country about hearing radio stations with no radio. One involves a machinist who had a few filings from work in his fillings that acted like a coherer and he could hear music in his head. Others have picked up strong stations in the vicinity in fence wires, gutters and downspouts, and so on. WLW out of Cincinnati in the thirties when they were running 500KW was the premier example of this.