@Training Wheels posted:KDKA is in Pittsburgh, PA and always has been since it was established by Westinghouse in 1920.
https://en.wikipedia.org/wiki/KDKA_(AM)
You also mentioned KDAK...that is in North Dakota.
I remember, from my misspent youth, listening to Wolfman Jack on a Mexican "pirate radio" station (probably XERB or XERF). It's my recollection that FCC had/has a limit of 50,000 watts on transmitters in US. As a result, some broadcasters set up shop in Mexico with 100,000 watt blasters. The station's call letters all began with "X". Fans of ZZ Top (that Little Old Band From Texas) will recall their song "Heard it on the X".
Sorry for the digression...now back to your regularly scheduled programming.
Ah ha!! So that is where "Heard it on the X" came from.