Confidence: Medium · Source: FCC ULS · As of 2026-09-12
KA4JDU callsign genealogy
Currently held by FRENZEL, JOHN C
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 KA4JDU'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 KA4JDU.
- FRENZEL, JOHN CTXgranted 2020-03-18