Confidence: Medium · Source: FCC ULS · As of 2026-09-11
KB4AC callsign genealogy
Currently held by WILLIAMS JR, ROBERT L
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 KB4AC's current licensee, walking backwards.
- THORNTON, JOHN KSCgranted 2012-02-27cancelled 2017-05-02
Successor callsigns
Callsigns held now by people who previously held KB4AC.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign KB4AC, oldest first.
- WILLIAMS JR, ROBERT L CA1998-09-18 → cancelled 2010-09-21
- THORNTON, JOHN K SC2017-05-02 active