Confidence: Medium · Source: FCC ULS · As of 2026-09-12
W9ABM callsign genealogy
Currently held by Collier, Michael J
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 W9ABM's current licensee, walking backwards.
Successor callsigns
Callsigns held now by people who previously held W9ABM.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign W9ABM, oldest first.
- PROCHASKA, CARL A IL2008-02-07 → cancelled 2020-04-17
- Collier, Michael J IL2026-07-17 active