Confidence: Medium · Source: FCC ULS · As of 2026-09-12
W6OST callsign genealogy
Currently held by HARLAN, JOHN S
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 W6OST's current licensee, walking backwards.
- KI6IHJcancelledJohn Harlan Memorial Amateur Radio ClubCAgranted 2007-03-06cancelled 2007-04-03
Successor callsigns
Callsigns held now by people who previously held W6OST.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign W6OST, oldest first.
- HARLAN, JOHN S CA1994-10-19 → cancelled 2006-10-20
- John Harlan Memorial Amateur Radio Club CA2017-01-17 active