Confidence: Medium · Source: FCC ULS · As of 2026-09-14
KO4MJJ callsign genealogy
Currently held by HEFLIN, DOUGLAS S
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 KO4MJJ'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 KO4MJJ.
- HEFLIN, DOUGLAS SNCgranted 2021-04-20