uls-tracker
Sign in
Confidence: Medium · Source: FCC ULS · As of 2026-09-14

K9OH callsign genealogy

Currently held by OST, BORJE W

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 K9OH's current licensee, walking backwards.

  1. WB4BLIcancelled· E
    Irwin, Billy LSCgranted 2003-03-29cancelled 2011-12-16
  2. KG4OYNcancelled· G
    Irwin, Billy LSCgranted 2000-12-08cancelled 2003-03-29
  3. KG4KSZcancelled· G
    Irwin, Billy LSCgranted 2000-12-08cancelled 2001-08-22

Successor callsigns

Callsigns held now by people who previously held K9OH.

No current licensee on record previously held this callsign.

All historical holders

Every license row we've seen with the callsign K9OH, oldest first.

  • OST, BORJE W WA
    2001-11-06 → cancelled 2009-11-26
  • Irwin, Billy L SC
    2021-11-09 active
← Back to K9OH License history →