This is where it gets murkey. If we only looked at 100 year old stations that NEVER changed frequencies, and still have the original call letters from that first license, how many would qualify...would any station?The KOY call letters only date back to 1929. The heritage of the original KFCB/KOY now belongs to KFYI. They were first on the air, but not licensed as a broadcaster (as KFCB) until 9/6/1922. It had been licensed as Amateur Radio station 6BBH before that.
The first broadcaster licensed as such in Phoenix was KDYW, on 5/15/1922. It died in early 1924.