Confidence: Medium · Source: FCC ULS · As of 2026-09-14
KO4ZSO callsign genealogy
Currently held by Green, 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 KO4ZSO'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 KO4ZSO.
- Green, John DGAgranted 2022-05-03