Confidence: Medium · Source: FCC ULS · As of 2026-09-14
KO4WKR callsign genealogy
Currently held by Heilmann, John 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 KO4WKR'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 KO4WKR.
- Heilmann, John DNCgranted 2022-02-26cancelled 2024-10-25