Faded Signals introduces a new source for radio-related advertising, articles and photos. This is U.S. Radio, a trade publication that apparently was in business from 1957 to 1961. You can find a complete archive on David Gleason’s outstanding American Radio History website.
This ad from 1961 welcomes newly inaugurated President John Kennedy and his administration to Washington and invites them to listen to WWDC-AM. Here’s an earlier entry about the station’s history.