Hi Standa and welcome!
The number of flights that RadarBox gets around Moscow is growing every day - especially as older airliners are being replaced with modern ones - many Boeing, Airbus, and Tupolev aircraft now use ADS-B, so will appear on the map. See the screenshot that I took just now.
As to your aerial, 40m sounds good, but if there are buildings, hills or trees in the wys, they will block the signals.
As to a Russian manual, it's not on Airnav's list, yet...
Rod