Confidence: Medium · Source: FCC ULS · As of 2026-09-12
K4UDQ callsign genealogy
Currently held by SOWINSKI, JAMES F
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 K4UDQ's current licensee, walking backwards.
Successor callsigns
Callsigns held now by people who previously held K4UDQ.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign K4UDQ, oldest first.
- SOWINSKI, JAMES W FL1994-03-22 → cancelled 2003-12-20
- SOWINSKI, JAMES F FL2026-01-22 active