Confidence: Medium · Source: FCC ULS · As of 2026-09-12
AD4ZU callsign genealogy
Currently held by Day, Christopher H
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 AD4ZU's current licensee, walking backwards.
- Day, Christopher HFLgranted 2009-03-06cancelled 2014-09-23
Successor callsigns
Callsigns held now by people who previously held AD4ZU.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign AD4ZU, oldest first.
- COLLINS, CARROLL J AL1994-11-09 → cancelled 2006-07-18
- Day, Christopher H FL2024-12-20 active