Confidence: Medium · Source: FCC ULS · As of 2026-09-12
N4ISP callsign genealogy
Currently held by Clark, Dayton T
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 N4ISP's current licensee, walking backwards.
- Clark, Dayton TGAgranted 2023-02-15cancelled 2023-05-31
Successor callsigns
Callsigns held now by people who previously held N4ISP.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign N4ISP, oldest first.
- DOUB, CYRUS H VA1998-03-16 → cancelled 2010-03-17
- Clark, Dayton T GA2023-05-31 active