Confidence: Medium · Source: FCC ULS · As of 2026-09-12
KG4CSJ callsign genealogy
Currently held by MASON, JOHN 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 KG4CSJ's current licensee, walking backwards.
- Johnston, Connard RSCgranted 2000-06-01cancelled 2006-11-14
Successor callsigns
Callsigns held now by people who previously held KG4CSJ.
- MASON, JOHN JGAgranted 2019-10-22
All historical holders
Every license row we've seen with the callsign KG4CSJ, oldest first.
- Johnston, Connard R SC2026-08-21 active
- MASON, JOHN J— → cancelled 1999-05-05