Confidence: Medium · Source: FCC ULS · As of 2026-09-12
KJ4MZ callsign genealogy
Currently held by Mertz Jr, Donald C
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 KJ4MZ's current licensee, walking backwards.
Successor callsigns
Callsigns held now by people who previously held KJ4MZ.
No current licensee on record previously held this callsign.