[bordercases]

This confused me too. Unless there are boosters of some kind, the power of a signal seems to follow a pretty predictable decay pattern. You would need to do a sample of the power around a certain radius and find some derivative in that field of where the power is increasing or decreasing the most in proportion to moving across that particular diameter in the circle. Then you've at least established a geodesic line to circumnavigate and hit the station at.

You've also narrowed down the total set of longitudes/latitudes based on the geometry of Russia and with high-confidence, assuming that the station's language can be taken as evidence of anything.

I am not an expert, this is just speculation. But that seems like a reasonable sketch of the problem solving method that would have to be involved.