Confidence: Medium · Source: FCC ULS · As of 2026-09-14
W4KDU callsign genealogy
Currently held by SWITZER, JONAS 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 W4KDU's current licensee, walking backwards.
- SWITZER, JONAS LKYgranted 2020-12-14cancelled 2022-05-03
Successor callsigns
Callsigns held now by people who previously held W4KDU.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign W4KDU, oldest first.
- STODDERT, THOMAS M MD1998-06-15 → cancelled 2010-06-16
- SWITZER, JONAS L KY2022-05-03 active