Confidence: Medium · Source: FCC ULS · As of 2026-09-12
K4GRZ callsign genealogy
Currently held by Sinclair, Christopher 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 K4GRZ's current licensee, walking backwards.
- Sinclair, Christopher MOHgranted 2021-11-15cancelled 2022-08-16
Successor callsigns
Callsigns held now by people who previously held K4GRZ.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign K4GRZ, oldest first.
- FREEMAN, ROBERT G FL2008-08-28 → cancelled 2020-11-20
- Sinclair, Christopher M FL2022-08-16 active