Confidence: Medium · Source: FCC ULS · As of 2026-09-12
K4SO callsign genealogy
Currently held by KILLMON, MARK 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 K4SO's current licensee, walking backwards.
Successor callsigns
Callsigns held now by people who previously held K4SO.
No current licensee on record previously held this callsign.