Confidence: Medium · Source: FCC ULS · As of 2026-09-14
W4ZDU callsign genealogy
Currently held by KING, RALPH 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 W4ZDU's current licensee, walking backwards.
Successor callsigns
Callsigns held now by people who previously held W4ZDU.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign W4ZDU, oldest first.
- KING, RALPH D TN1996-05-22 → cancelled 2008-05-23
- SMITH, RUSSELL KY2020-03-06 active