Confidence: Medium · Source: FCC ULS · As of 2026-09-12
KF4RJA callsign genealogy
Currently held by Achtenberg, Robert 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 KF4RJA's current licensee, walking backwards.
- Achtenberg, Robert JGAgranted 2021-05-17cancelled 2022-03-05
Successor callsigns
Callsigns held now by people who previously held KF4RJA.
All historical holders
Every license row we've seen with the callsign KF4RJA, oldest first.
- Achtenberg, Robert J GA2022-03-05 → cancelled 2023-04-01
- THOMAS, JAMES M— → cancelled 1997-12-03