[Doublej]

I currently have a wifi router sitting on the floor of the third floor of my house. Performance is screaming if I am sing my laptop on the third floor (50Mbps) but performance is typically slower (~12Mbps) if I use my laptop on the second floor. The router antennas are pointing straight up.

Are my antennas oriented properly to maximize performance? Would hanging the router upside down or pointing the antennas parallel to the floor improve performance?

It is a "noisy" environment. There are over 15 wireless networks that show up on a scan but that should not make a difference when it comes to antenna orientation for maximum performance, should it?

[jqp]

There is definitely a geometry for wi-fi signals depending on type of antenna, frequency (2.4 and 5GHz) and orientation.

This is an older but pretty good article that covers many of your issues, and if you search you can get more recent articles for current wireless router technologies, also check tech websites for current router roundups and home wifi articles.

http://blog.serverfault.com/2011/12/12/a-studied-approach-at-wifi-part-1/

[JohnR]

I read an article that measured throughput with the new (ish) 802.11ac Airport Extreme. Also the older model. The largest effect was distance from the base station and number of walls in between. I don't recall anything about antenna orientation but if high performance really is required I got the impression that running wire (Ethernet) to wireless repeaters on each floor was the best approach.