Confidence: Medium · Source: FCC ULS · As of 2026-09-14
N9DU callsign genealogy
Currently held by KOLCSEY, ISTVAN
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 N9DU's current licensee, walking backwards.
Successor callsigns
Callsigns held now by people who previously held N9DU.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign N9DU, oldest first.
- KOLCSEY, ISTVAN WI2012-06-06 → cancelled 2024-05-18
- Vandenlangenberg, Evan W WI2024-06-11 active