Confidence: Medium · Source: FCC ULS · As of 2026-09-12
WM4X callsign genealogy
Currently held by PENZO, MICHAEL A
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 WM4X's current licensee, walking backwards.
- PENZO, MICHAEL AVAgranted 2007-01-31cancelled 2010-03-16
Successor callsigns
Callsigns held now by people who previously held WM4X.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign WM4X, oldest first.
- COLLSON, ERWIN L AR1998-02-20 → cancelled 2010-02-23
- PENZO, MICHAEL A VA2020-01-06 active