Confidence: Medium · Source: FCC ULS · As of 2026-09-12
KD4TLM callsign genealogy
Currently held by COSTELLO, TOBIN M
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 KD4TLM's current licensee, walking backwards.
- Mann, Terry LFLgranted 2026-06-23cancelled 2026-07-11
Successor callsigns
Callsigns held now by people who previously held KD4TLM.
No current licensee on record previously held this callsign.
All historical holders
Every license row we've seen with the callsign KD4TLM, oldest first.
- COSTELLO, TOBIN M FL1992-10-06 → cancelled 2004-10-07
- Mann, Terry L FL2026-07-11 active