Confidence: Medium · Source: FCC ULS · As of 2026-09-12
KC1SF callsign genealogy
Currently held by Special Forces Brothers Amateur Radio Club
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 KC1SF's current licensee, walking backwards.
- KC1DOAcancelledSpecial Forces Brothers Amateur Radio ClubMAgranted 2015-04-09cancelled 2015-04-28
Successor callsigns
Callsigns held now by people who previously held KC1SF.
- TANKIN, HARRY JPAgranted 2020-04-15
All historical holders
Every license row we've seen with the callsign KC1SF, oldest first.
- TANKIN, HARRY J PA2000-06-14 → cancelled 2000-06-27
- Special Forces Brothers Amateur Radio Club MA2025-04-01 active