Confidence: Medium · Source: FCC ULS · As of 2026-09-14
KJ4UDR callsign genealogy
Currently held by Knappenberger, Jason 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 KJ4UDR's current licensee, walking backwards.
The current licensee has not held any other callsign on record.
Successor callsigns
Callsigns held now by people who previously held KJ4UDR.
- Knappenberger, Jason TFLgranted 2020-02-29