This may be a little off topic, but here goes anyway.

I have read somewhere that vertical antennas radiate almost nothing
below the lowest elevation of the antenna.

So, I was wondering if a wireless router also radiates almost nothing
below the router. (The antenna of a wireless router is usually
pointing up.) These devices usually operate at 2.45 GHz.

I know that routers usually have other means of security, but I was
wondering if I could also locate the router such that the radiation
was limited or non-existent in one direction.

Thanks, jimbo