Confidence: Medium · Source: FCC ULS · As of 2026-09-12
K0LLO callsign genealogy
Currently held by WARTBURG, RONALD 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 K0LLO's current licensee, walking backwards.
- WARTBURG, RONALD JTXgranted 2016-03-21cancelled 2016-04-15
Successor callsigns
Callsigns held now by people who previously held K0LLO.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign K0LLO, oldest first.
- WARTBURG, ROBERT L CA2006-01-30 → cancelled 2014-04-24
- WARTBURG, RONALD J TX2026-02-27 active