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Confidence: Medium · Source: FCC ULS · As of 2026-09-12

K4SF callsign genealogy

Currently held by ENGLUND, JOHN B

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 K4SF's current licensee, walking backwards.

  1. KA3Cactive· E
    CASTELLANOS, LUIS MGAgranted 2024-05-07
  2. N1LMCcancelled· E
    CASTELLANOS, LUIS MPAgranted 2008-11-07cancelled 2014-05-17
  3. KJ4GEScancelled· G
    CASTELLANOS, LUIS MMAgranted 2008-08-21cancelled 2008-11-07

Successor callsigns

Callsigns held now by people who previously held K4SF.

No current licensee on record previously held this callsign.

All historical holders

Every license row we've seen with the callsign K4SF, oldest first.

  • ENGLUND, JOHN B CT
    2009-04-24 → cancelled 2010-04-09
  • MITCHELL, THOMAS E VA
    2022-03-08 active
← Back to K4SF License history →