Confidence: Medium · Source: FCC ULS · As of 2026-09-12
AB0U callsign genealogy
Currently held by Baumgardner, Jonathan 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 AB0U's current licensee, walking backwards.
Successor callsigns
Callsigns held now by people who previously held AB0U.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign AB0U, oldest first.
- Vollrath, Edwin A MN2007-11-27 → cancelled 2020-02-07
- Baumgardner, Jonathan A CO2020-03-28 active