Confidence: Medium · Source: FCC ULS · As of 2026-09-12
KB4JFS callsign genealogy
Currently held by NIEVES, JAMES 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 KB4JFS's current licensee, walking backwards.
- SWARTZ SR, MARK PMOgranted 2021-11-19cancelled 2021-12-17
Successor callsigns
Callsigns held now by people who previously held KB4JFS.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign KB4JFS, oldest first.
- NIEVES, JAMES M FL1994-10-24 → cancelled 2006-10-25
- SWARTZ SR, MARK P MO2021-12-17 active