Confidence: Medium · Source: FCC ULS · As of 2026-09-12
AC1O callsign genealogy
Currently held by PIRIS, ADRIAN
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 AC1O's current licensee, walking backwards.
Successor callsigns
Callsigns held now by people who previously held AC1O.
- DEEMER, WALTER RFLgranted 2026-08-21
All historical holders
Every license row we've seen with the callsign AC1O, oldest first.
- GRANT, DARYL L ME2010-03-19 → cancelled 2022-06-01
- PIRIS, ADRIAN MA2022-07-26 active