Radar doesn't exactly tell you the size of of a contact. Sure, you can measure the power of the return signal, correct for distance and get something that loosely correlates with size. But it correlates much more strongly with other things.

You're also making the assumption here that it was a modern Russian system. This wasn't exactly close to the current fighting, its entirely possible this radar was manufactured in the Soviet Union. I don't think those receive a lot (or any) civilian broadcasts.