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

K4EXP callsign genealogy

Currently held by Montero, Marcial

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 K4EXP's current licensee, walking backwards.

  1. K4HWYcancelled· T
    Montero, MarcialNCgranted 2021-05-28cancelled 2022-07-09
  2. W4MXMcancelled· T
    Montero, MarcialNCgranted 2020-06-01cancelled 2021-05-28
  3. KO4DIMcancelled· T
    Montero, MarcialNCgranted 2020-05-11cancelled 2020-06-01

Successor callsigns

Callsigns held now by people who previously held K4EXP.

  1. K4YYactive· E
    SWAIN, MICHAEL JFLgranted 2018-01-03

All historical holders

Every license row we've seen with the callsign K4EXP, oldest first.

  • SWAIN, MICHAEL J FL
    2015-04-07 → cancelled 2018-01-03
  • Montero, Marcial NC
    2022-07-09 active
← Back to K4EXP License history →