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

NT1S callsign genealogy

Currently held by Schroder, Robert T

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 NT1S's current licensee, walking backwards.

  1. N2RTScancelled· E
    Schroder, Robert TCTgranted 2021-09-04cancelled 2023-05-13
  2. KO4SQTcancelled· T
    Schroder, Robert TVAgranted 2021-08-17cancelled 2021-09-04

Successor callsigns

Callsigns held now by people who previously held NT1S.

  1. KB1Dactive· E
    Helms, Gregory PMEgranted 2021-04-24
  2. KZ1APcancelled· E
    Helms, Gregory PMEgranted 2020-11-03cancelled 2020-11-24

All historical holders

Every license row we've seen with the callsign NT1S, oldest first.

  • HEISER, WILLIAM W MA
    2008-06-30 → cancelled 2020-09-23
  • Helms, Gregory P ME
    2020-10-14 → cancelled 2020-11-03
  • Helms, Gregory P ME
    2020-11-24 → cancelled 2021-04-24
  • Schroder, Robert T MD
    2023-05-13 active
← Back to NT1S License history →