Confidence: Medium · Source: FCC ULS · As of 2026-09-14
K0XTX callsign genealogy
Currently held by McCarthy III, William 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 K0XTX's current licensee, walking backwards.
- McCarthy III, William MCOgranted 2022-05-10cancelled 2024-03-05
Successor callsigns
Callsigns held now by people who previously held K0XTX.
- Gruber, Aaron AMNgranted 2018-07-27
All historical holders
Every license row we've seen with the callsign K0XTX, oldest first.
- Gruber, Aaron A MN2016-05-03 → cancelled 2018-07-27
- McCarthy III, William M CO2024-03-05 active