What about the neighbor above/below your apartment? A ceiling of ferroconcrete is a good blocker (or a good multiplier?)
From my apartment, I can see a telecommunication tower, about 1.2 kilometers away. Wondering what it could pick up with enterprise grade antennas if it wanted to. maybe the other monitors around would disturb the signals?
https://www.usenix.org/legacy/events/sec09/tech/full_papers/...