Confidence: Medium · Source: FCC ULS · As of 2026-09-12
KU4SP callsign genealogy
Currently held by CASTILLO, RENE R
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 KU4SP's current licensee, walking backwards.
The current licensee has not held any other callsign on record.
Successor callsigns
Callsigns held now by people who previously held KU4SP.
- CASTILLO, RENE RVAgranted 2021-01-06