Confidence: Medium · Source: FCC ULS · As of 2026-09-14
KO4BL callsign genealogy
Currently held by BLACKWELL III, JOEL D
The FCC publishes a previous_call_sign on
every amateur license — a self-link to the licensee's prior callsign.
Following those links produces the chain below.
Previous callsigns
Older callsigns held by KO4BL's current licensee, walking backwards.
- Baldwin, William BFLgranted 2021-11-29cancelled 2025-04-26
Successor callsigns
Callsigns held now by people who previously held KO4BL.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign KO4BL, oldest first.
- BLACKWELL III, JOEL D SC1992-05-05 → cancelled 2004-05-06
- Baldwin, William B FL2025-04-26 active