Confidence: Medium · Source: FCC ULS · As of 2026-09-14
KY4SJ callsign genealogy
Currently held by Byun, Soo Duk
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 KY4SJ's current licensee, walking backwards.
- Byun, Soo DukNCgranted 2021-07-02cancelled 2022-10-21
Successor callsigns
Callsigns held now by people who previously held KY4SJ.
No current licensee on record previously held this callsign.