Confidence: Medium · Source: FCC ULS · As of 2026-09-12
K4SM callsign genealogy
Currently held by ACHTERHOF, MARVIN L
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 K4SM's current licensee, walking backwards.
Successor callsigns
Callsigns held now by people who previously held K4SM.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign K4SM, oldest first.
- HINEGARDNER, JOHN R FL1989-08-15 → cancelled 1994-12-31
- ACHTERHOF, MARVIN L SC2020-12-02 active