Confidence: Medium · Source: FCC ULS · As of 2026-09-14
W0TKO callsign genealogy
Currently held by Barth, Matthew J
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 W0TKO's current licensee, walking backwards.
- Hardie, RossSDgranted 2023-06-29cancelled 2023-07-18
Successor callsigns
Callsigns held now by people who previously held W0TKO.
- Hardie, RossSDgranted 2024-02-21
All historical holders
Every license row we've seen with the callsign W0TKO, oldest first.
- Barth, Matthew J CO2007-07-03 → cancelled 2019-07-04
- Hardie, Ross SD2023-07-18 → cancelled 2024-02-21