With all due respect, that list is a bit silly. Example: I have a netgear access point and I use it at home (150 years old european house with thick brick walls). Each walls eats 20 dB, so no signal after the third wall. To solve the problem, I bought a separate patch antenna with 8 dB of gain. In free space, with that extra antenna main lobe pointed at the Nokia, I can probably reach over 300 meters.
So which is the correct answer: 3 walls or 300 meters?
BTW: I work in antennas. I can easily point you to designs with 20 dB of gain, and they would boost your contacts quite remarkably. A few kilometers, line of sight, can relatively easily be done for wifi.
FWIW: the 770 appears to be quite sensitive actually. It certainly beats my Apple powerbook and the CF card for my (now retired) Zaurus.
Good connection at least 50ft
-Unable to make NFS connections