Confidence: Medium · Source: FCC ULS · As of 2026-09-12
K4DFH callsign genealogy
Currently held by HAMMACK, DAVID F
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 K4DFH's current licensee, walking backwards.
- HAMMACK, DAVID FSCgranted 2014-11-13cancelled 2018-06-02
Successor callsigns
Callsigns held now by people who previously held K4DFH.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign K4DFH, oldest first.
- PROBST, FRED J FL1994-07-15 → cancelled 2006-07-18
- HAMMACK, DAVID F SC2018-06-02 active