It is Hrvatska Radio, located at Zadar, Croatia. Hrvatska means
Croatia; one of the independent states of the former Yugoslavia. The
transmitter is located near 44°06'N, 15°15'E.
Here in north central Oklahoma the signal seems to be best between
0130 and 0300 UTC. Last night it was penetrating through KMOX's HD
(IBOC) signal with a good strength as heard on an E100. Not bad for a
distance of approximately 8791 km. / 5462 miles.
36°22'51"N / 97°26'35"W
(near Perry OK)