Confidence: Medium · Source: FCC ULS · As of 2026-09-14
KK0O callsign genealogy
Currently held by O'Brien, Mark 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 KK0O's current licensee, walking backwards.
- OBRIEN, MARKKSgranted 2017-06-12cancelled 2018-02-24
Successor callsigns
Callsigns held now by people who previously held KK0O.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign KK0O, oldest first.
- SMITH, JAY S MN2005-12-06 → cancelled 2018-02-06
- O'Brien, Mark A KS2018-02-24 active