Confidence: Medium · Source: FCC ULS · As of 2026-09-12
K0TWM callsign genealogy
Currently held by DUNCAN, DAVID R
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 K0TWM's current licensee, walking backwards.
- Mathews IV, Theodore WIAgranted 2018-12-11cancelled 2019-08-02
Successor callsigns
Callsigns held now by people who previously held K0TWM.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign K0TWM, oldest first.
- DUNCAN, DAVID R MN1988-07-19 → cancelled 2000-07-20
- Mathews IV, Theodore W MD2019-08-02 active