Confidence: Medium · Source: FCC ULS · As of 2026-09-12
AJ4BO callsign genealogy
Currently held by NIELSEN, JOHN E
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 AJ4BO's current licensee, walking backwards.
Successor callsigns
Callsigns held now by people who previously held AJ4BO.
No current licensee on record previously held this callsign.