Confidence: Medium · Source: FCC ULS · As of 2026-09-12
N4DTO callsign genealogy
Currently held by Smith, William R
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 N4DTO's current licensee, walking backwards.
- Smith, William RNCgranted 2016-07-18cancelled 2016-08-05
Successor callsigns
Callsigns held now by people who previously held N4DTO.
- Smith, William RMOgranted 2023-07-14
All historical holders
Every license row we've seen with the callsign N4DTO, oldest first.
- SIEGENTHALER, PETER W FL1996-11-04 → cancelled 2007-04-04
- Smith, William R MO2016-08-05 → cancelled 2023-07-14