Confidence: Medium · Source: FCC ULS · As of 2026-09-12
K4MJM callsign genealogy
Currently held by MAC PHERSON, WILLIAM
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 K4MJM's current licensee, walking backwards.
- MITCHONIE, MARK JNCgranted 2016-11-18cancelled 2016-12-16
Successor callsigns
Callsigns held now by people who previously held K4MJM.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign K4MJM, oldest first.
- MAC PHERSON, WILLIAM FL2000-04-07 → cancelled 2012-07-04
- MITCHONIE, MARK J NC2016-12-16 active