Mark J Underdown
Active- Service
- Amateur
- Class
- Technician
- Location
- KNOXVILLE, TN
- FRN
- 0037659448
- Granted
- Jun 10, 2026
- Expires
- Jun 10, 2036
FCC Amateur and GMRS license lookup
Search public FCC ULS records by callsign, FRN, name, or location.
KR4MTD
- Callsign
- Try W1AW, or enter several callsigns separated by commas.
- FRN
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- Advanced
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