Confidence: Medium · Source: FCC ULS · As of 2026-09-12
K6TO callsign genealogy
Currently held by GRISMORE, ROGER
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 K6TO's current licensee, walking backwards.
Successor callsigns
Callsigns held now by people who previously held K6TO.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign K6TO, oldest first.
- GRISMORE, ROGER CA2010-09-23 → cancelled 2022-11-22
- Sieh, Dai D CA2022-12-09 active