Confidence: Medium · Source: FCC ULS · As of 2026-09-12
N1GMB callsign genealogy
Currently held by Butterfield, Glenn 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 N1GMB's current licensee, walking backwards.
Successor callsigns
Callsigns held now by people who previously held N1GMB.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign N1GMB, oldest first.
- THALHEIMER, GLENN R CA2004-03-16 → cancelled 2016-05-25
- Butterfield, Glenn M RI2026-05-05 active