Confidence: Medium · Source: FCC ULS · As of 2026-09-14
KO4UBJ callsign genealogy
Currently held by Mikkelsen, Donald J
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 KO4UBJ's current licensee, walking backwards.
The current licensee has not held any other callsign on record.
Successor callsigns
Callsigns held now by people who previously held KO4UBJ.
- Mikkelsen, Donald JVAgranted 2021-10-15cancelled 2026-08-21