OurAirports has records for 10 different navaids with the identifier "U". Please select the one you'd like to view.
Argentina
307 KHz (U ..-)
..-
Azerbaijan
113 KHz (U ..-)
Bulgaria
465 KHz (U ..-)
China
272 KHz (U ..-)
Cuba
287 KHz (U ..-)
Finland
372 KHz (U ..-)
Kazakhstan
214 KHz (U ..-)
708 KHz (U ..-)
Ukraine
617 KHz (U ..-)
Uzbekistan
390 KHz (U ..-)