Confidence: Medium · Source: FCC ULS · As of 2026-09-12
K6SFK callsign genealogy
Currently held by Koster, Stephen F
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 K6SFK's current licensee, walking backwards.
- Koster, Stephen FCAgranted 2010-07-22cancelled 2010-08-13
Successor callsigns
Callsigns held now by people who previously held K6SFK.
- Koster, Steve FCAgranted 2021-11-16