This is not your typical post, but I struggled enough with this that I assumed others could benefit from it as well.
I have a first gen Nexus 7 (N7) and had extremely bad Wi-Fi signal / reception over the past few months. Not only was the signal bad, the throughput was miserable (5 mbps). I purchased a TRENDnet TEW-811DRU which I flashed DD-WRT onto and installed it as an additional access point to help alleviate the problem. It barely helped. I played around with wireless channels, frequencies (2.4 vs 5.0), and more. Nothing would make it better despite the router being 8 feet from the tablet.
Eventually I discovered the problem, which seems to be a bit common in these generations. As with most tablets, the 7 has been dropped a time or two. It turns out that the Wi-Fi antenna is actually connected from the main unit to the rear case. On my 7, the upper left corner of the case was actually snapped open about a 1/16th of an inch. Pressing the case back in (I had to press fairly hard) instantly fixed all of the wireless signal problems.
So there you have it. If you are having terrible wireless reception or signal issues, check your case and make sure it's fully snapped in. It may be an easier fix than you thought!
