Confidence: Medium · Source: FCC ULS · As of 2026-09-14
W4TWK callsign genealogy
Currently held by FITZPATRICK JR, WILLIAM O
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 W4TWK's current licensee, walking backwards.
- Knecht, Thomas WGAgranted 2009-08-17cancelled 2009-09-11
Successor callsigns
Callsigns held now by people who previously held W4TWK.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign W4TWK, oldest first.
- FITZPATRICK JR, WILLIAM O AL1993-06-08 → cancelled 2005-06-09
- Knecht, Thomas W GA2019-07-02 active