Confidence: Medium · Source: FCC ULS · As of 2026-09-12
K4DEF callsign genealogy
Currently held by DeFoore, Matthew 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 K4DEF's current licensee, walking backwards.
- DeFoore, Matthew CNHgranted 2026-04-22cancelled 2026-06-02
Successor callsigns
Callsigns held now by people who previously held K4DEF.
- Roberts, James TMOgranted 2022-12-16
All historical holders
Every license row we've seen with the callsign K4DEF, oldest first.
- Overdorff, William R TN2008-12-09 → cancelled 2021-03-06
- Roberts, James T MO2022-01-21 → cancelled 2022-12-16
- DeFoore, Matthew C NH2026-06-02 active