Confidence: Medium · Source: FCC ULS · As of 2026-09-12
AD4IO callsign genealogy
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 AD4IO's current licensee, walking backwards.
The current licensee has not held any other callsign on record.
Successor callsigns
Callsigns held now by people who previously held AD4IO.
- JOHNSTON JR, EDWARD CVAgranted 2016-10-04