Unid 1521
I assume it is China International in Russian with their 8 mast ARRT antenna.
https://www.mwlist.org/mwlist_quick_and_easy.php?area=2&kHz=1521
It is also good audible on the Novosibirsk SDR.
Please have a look at the site:
One of the 2 ARRT 8 mast systems (quadrat with reflectors?) is gone:
44.15737932418653,86.89256697621546
A 4 mast ARRT antenna is also gone (Quadrat without reflectors?):
https://www.mwlist.org/mwlist_quick_and_easy.php?area=2&kHz=1521
Marco (2023-03-01)