Confidence: Medium · Source: FCC ULS · As of 2026-09-12
W9FRZ callsign genealogy
Currently held by BROWN, JOHN S
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 W9FRZ's current licensee, walking backwards.
- Zuhlsdorf, John TWIgranted 2013-07-24cancelled 2015-11-03
Successor callsigns
Callsigns held now by people who previously held W9FRZ.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign W9FRZ, oldest first.
- BROWN, JOHN S IL1994-11-21 → cancelled 2006-11-22
- Zuhlsdorf, John T FL2025-11-19 active