Confidence: Medium · Source: FCC ULS · As of 2026-09-12
WA4ATZ callsign genealogy
Currently held by HILL, ROBERT 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 WA4ATZ's current licensee, walking backwards.
- Herrenkohl, Mark JWAgranted 2018-11-13cancelled 2018-12-01
Successor callsigns
Callsigns held now by people who previously held WA4ATZ.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign WA4ATZ, oldest first.
- HILL, ROBERT H VA1997-02-21 → cancelled 2009-02-24
- Herrenkohl, Mark J WA2018-12-01 active