What can be on a map with such coverage?

Question

mobile connection

I looked at the Tinkov coverage map, and in the Volgograd region - this. I'm not in the subject of telephony, so it became interesting, but I don't know where to ask, except here. Tell me why such a circle is perfect? What's there?

Answer 1

The distance from the base station is limited not only by the terrain, but also by the value of the timing advance parameter for the base station. Which, if explained on the fingers, indicates what the maximum delay of the signal passing from the subscriber device to the BS can be. Therefore, even if the signal level is sufficient (say, your phone is attached to a directional antenna), but TA is exceeded (for example, to the BS - 80 kilometers), there will be no connection.
That's why the circle is even.