Try pointing a directional antenna (including UHF loops) straight UP. I noticed this in my place a while ago but didn't really explore it until recently. I definitely have the most signal coming from above. Probably largely because the house has a radiant barrier which effectively blocks signal, so the majority of it comes in through the roof.

Sounds like my ad hoc SETI science project. :)

Now if only indoor antennas come with a 3D/360 twistable mount.