Confidence: Medium · Source: FCC ULS · As of 2026-10-24
K9COS callsign genealogy
Currently held by BALCOM, EUGENE F
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 K9COS's current licensee, walking backwards.
- Hamburger, Mark LCOgranted 2026-03-10cancelled 2026-09-09
Successor callsigns
Callsigns held now by people who previously held K9COS.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign K9COS, oldest first.
- BALCOM, EUGENE F TN2012-08-24 → cancelled 2024-12-04
- Hamburger, Mark L CO2026-09-09 active