Confidence: Medium · Source: FCC ULS · As of 2026-09-12
KC4MRZ callsign genealogy
Currently held by CARDO, CHARLES 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 KC4MRZ's current licensee, walking backwards.
- Holtzworth, Martha KKYgranted 2016-07-13cancelled 2025-08-15
Successor callsigns
Callsigns held now by people who previously held KC4MRZ.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign KC4MRZ, oldest first.
- CARDO, CHARLES R FL1990-07-03 → cancelled 2002-07-04
- Holtzworth, Martha K KY2025-08-15 active