Magadan Area Control Center works flights on polar routes, often handed over from Gander. Magadan Radio can normally be heard on 4712, 8837 and 11390 kHz during the overnight hours from the Western USA. Other published frequencies include: 6585, 13265 and 15030 kHz. Unfortunately the aircraft are just out of my reception range given the conditions, but the high powered transmitter from their control facilities are quite easy to pick up.
Here is a recording of Magadan Radio taken from my archive.