Confidence: Medium · Source: FCC ULS · As of 2026-09-12
AD4ZH callsign genealogy
Currently held by Hubbard, John 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 AD4ZH's current licensee, walking backwards.
- Hubbard, John TFLgranted 2021-02-03cancelled 2021-05-04
Successor callsigns
Callsigns held now by people who previously held AD4ZH.
- ZIMMATORE JR, JOHN JGAgranted 1998-04-22cancelled 2006-01-07
All historical holders
Every license row we've seen with the callsign AD4ZH, oldest first.
- Hubbard, John T FL2021-05-04 active
- —— → cancelled 1998-04-22