Confidence: Medium · Source: FCC ULS · As of 2026-09-14
W9WKT callsign genealogy
Currently held by KOSTRZAK, JOHN M
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 W9WKT's current licensee, walking backwards.
- PITTELKOW, JOSEPHWAgranted 2023-12-16cancelled 2024-01-05
Successor callsigns
Callsigns held now by people who previously held W9WKT.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign W9WKT, oldest first.
- KOSTRZAK, JOHN M AR2006-10-10 → cancelled 2018-12-07
- PITTELKOW, JOSEPH WA2024-01-05 active