Confidence: Medium · Source: FCC ULS · As of 2026-09-12
K9BTH callsign genealogy
Currently held by Pham, Huy
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 K9BTH's current licensee, walking backwards.
- Pham, HuyAZgranted 2026-05-09cancelled 2026-05-29
Successor callsigns
Callsigns held now by people who previously held K9BTH.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign K9BTH, oldest first.
- BLUMBERG, SIDNEY IL2006-12-22 → cancelled 2019-03-22
- Pham, Huy AZ2026-05-29 active