Confidence: Medium · Source: FCC ULS · As of 2026-09-14
KJ4ZU callsign genealogy
Currently held by SPEARS, RICHARD N.
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 KJ4ZU's current licensee, walking backwards.
- Cardwell, Jason MFLgranted 2010-04-13cancelled 2011-02-01
Successor callsigns
Callsigns held now by people who previously held KJ4ZU.
- SPEARS, RICHARD NFLgranted 2017-06-20
All historical holders
Every license row we've seen with the callsign KJ4ZU, oldest first.
- Cardwell, Jason M FL2020-11-13 active
- SPEARS, RICHARD N.— → cancelled 1997-09-17