Confidence: Medium · Source: FCC ULS · As of 2026-09-12
K4VM callsign genealogy
Currently held by Colburn, William 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 K4VM's current licensee, walking backwards.
- Colburn, William TWAgranted 2017-03-15cancelled 2017-04-25
Successor callsigns
Callsigns held now by people who previously held K4VM.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign K4VM, oldest first.
- COLBURN, MARTHA H AZ2009-04-08 → cancelled 2015-05-06
- Colburn, William T FL2017-04-25 active