Confidence: Medium · Source: FCC ULS · As of 2026-09-14
KR4MDM callsign genealogy
Currently held by Martens, Mark 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 KR4MDM's current licensee, walking backwards.
- Martens, Mark DFLgranted 2025-05-06cancelled 2025-06-21
Successor callsigns
Callsigns held now by people who previously held KR4MDM.
No current licensee on record previously held this callsign.