Confidence: Medium · Source: FCC ULS · As of 2026-09-14
KD7MTB callsign genealogy
Currently held by Castillo III, Joseph J
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 KD7MTB's current licensee, walking backwards.
- Castillo III, Joseph JAZgranted 2023-09-13cancelled 2023-10-03
Successor callsigns
Callsigns held now by people who previously held KD7MTB.
- K0HSUactiveHEART - Hospital Emergency Amateur Radio TeamORgranted 2021-03-24
All historical holders
Every license row we've seen with the callsign KD7MTB, oldest first.
- HEART - Hospital Emergency Amateur Radio Team OR2001-04-17 → cancelled 2001-05-08
- Castillo III, Joseph J AZ2023-10-03 active