South along Russia they have VHF remote transmitters at St. Paul Island (SPY) and Shemya (SYA) which seems to cover most of the airspace, although they also use HF (San Francisco) in this area as well for the gaps in VHF coverage.
I've been listening to San Francisco on 6655 this morning (1400-1600 UTC) and hearing all the eastbound traffic through Anchorage airspace check on for selcal checks as they cross the boundary, but not hearing any of the many westbound flights routing via R220 and R580. Probably stay on VHF ? You will get the westbound flights on HF as the pass into Tokyo airspace (Tokyo - 2932, 5628, 8951, 11330).
There was an eastbound B744 (NRT-ANC) routing via R591 passing over SYA and SPY giving position reports on 6655 (CPDLC must have been inop). Was told to "monitor" Anchorage on 119.10 when 150 nm from SYA but told to stay on 6655 for the position reports. Position reports were sent on 6655 at AAMYY, SYA, AMOND, ALDOZ, then told to "contact" Anchorage on 119.10 at position ALUFF.
