Confidence: Medium · Source: FCC ULS · As of 2026-09-12
KP4GR callsign genealogy
Currently held by MONTALVO CASTRO, NORBERTO
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 KP4GR's current licensee, walking backwards.
- MONTALVO CASTRO, NORBERTOPRgranted 2020-09-14cancelled 2023-03-24
Successor callsigns
Callsigns held now by people who previously held KP4GR.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign KP4GR, oldest first.
- HERNANDEZ ALONSO, PELEGRIN PR2008-03-22 → cancelled 2020-03-26
- MONTALVO CASTRO, NORBERTO PR2023-03-24 active