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

N4SZ callsign genealogy

Currently held by BILLSTROM, DAVID J

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 N4SZ's current licensee, walking backwards.

  1. W7FRLcancelled· E
    BILLSTROM, DAVID JNCgranted 2023-06-22cancelled 2024-09-28
  2. N7UUKcancelled· G
    BILLSTROM, DAVID JNCgranted 2011-11-15cancelled 2013-09-07

Successor callsigns

Callsigns held now by people who previously held N4SZ.

  1. NO7Jactive
    Yellow Jacket Contest ClubIDgranted 2022-09-09

All historical holders

Every license row we've seen with the callsign N4SZ, oldest first.

  • Foster Sr, Stephen J SC
    2017-01-09 → cancelled 2018-01-18
  • Yellow Jacket Contest Club WA
    2020-02-11 → cancelled 2022-09-09
  • BILLSTROM, DAVID J VA
    2024-09-28 active
← Back to N4SZ License history →