Confidence: Medium · Source: FCC ULS · As of 2026-09-12
W1SO callsign genealogy
Currently held by CARPENTER, WILLIAM P
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 W1SO's current licensee, walking backwards.
- Kerrigan, Ellen JMEgranted 2017-09-15
- PHILLIPS, ROBERT EMAgranted 2022-04-12
- da Costa Roque, Alexander JMAgranted 2019-12-17cancelled 2021-11-27
- Da Costa Roque, Alexander JMAgranted 2019-09-28cancelled 2019-12-17
- Da Costa Roque, Alexander JMAgranted 2019-09-10cancelled 2019-09-28
- Da Costa Roque, Alexander JMAgranted 2019-04-18cancelled 2019-09-10
Successor callsigns
Callsigns held now by people who previously held W1SO.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign W1SO, oldest first.
- CARPENTER, WILLIAM P CT1994-10-27 → cancelled 2003-08-23
- Kerrigan, Bruce R ME2025-07-08 active