Confidence: Medium · Source: FCC ULS · As of 2026-09-12
K4OPS callsign genealogy
Currently held by SHILLING, HAROLD 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 K4OPS's current licensee, walking backwards.
- Costanzo, Louis JVAgranted 2019-07-25cancelled 2019-08-20
Successor callsigns
Callsigns held now by people who previously held K4OPS.
- SHILLING, HAROLD TVAgranted 2012-05-18cancelled 2012-11-10
All historical holders
Every license row we've seen with the callsign K4OPS, oldest first.
- SHILLING, HAROLD T VA2002-08-13 → cancelled 2012-05-18
- Costanzo, Louis J VA2019-08-20 active