After moving last December, I faced the problem of extending the wireless network to the whole house, now bigger and extended over more floors. The first thing I had in mind was to buy a powerful GHz amplifier and the correspondent antenna.
After browsing a bit, I decided to try another solution, the one using the power network. The idea was to buy the adapter for the AC and then another RJ-45 adapter. At the shop I noticed a quite attractive solution, the Netgear wireless extender Kit WGXB102, where the second device is not just an RJ-45, but a wireless access point at such.
Here, in case you are interested, the steps to install it with the maximum security possible:
1. Notice all the codes on the back of the two adapters; they'll be needed in the configuration.
2. Just plug the base station to your router and to the AC network. Then plug the second adapter. The solution already works fine, without any security. The new wireless network is called NETGEAR and has no encryption at all. As they mention, avoid any kind of additional adapter/split and plug the two devices directly to the AC network.
3. Start measuring the speed you have in the new wireless environment depending on the AC plug. Do not underestimate this step. Due to the AC network structure in your house, you can experience very different results. the results are not at all depending on the distance between the two adapters, but on the AC network cables themselves.
3.1. If we call x the maximum speed you have, by measuring it with speedmeter.nl, I found a 0.2x speed quite near to the bridge and an acceptable 0.6x upstairs where I'm writing now.
4. After you've decided for the best plugs, start the security settings. In doing this, you've to log-on in the wireless adapter as first; if you dont reach it (192.168.0.101) it is due to a subnet mask issue. Force your address to a 192.168.0.x by setting it directly in the TCP/IP settings.
5. After the logon:
5.1. Change the password of the wireless extender (Maintenance-Set Password)
5.2. Change the password of the AC network (Setup-Wall Plug Settings)
5.3. Change the password of the AC bridge (you dont need to install the software; you can do it within the wireless extender interface: Setup-Wall Plug Settings-Add. Here you need the brige password you noticed at the point 1)
5.4. Change the name of the network (Setup-Wireless settings. Change and then apply)
5.5. Set the Mac address filtering (Setup-Wireless settings->Setup access list. Check the Turn Access Control On; add the Mac addresses and then apply)
5.6. Set the encryption (Setup-Wireless settings. Change and then apply). I set a 128 WEP.
5.7. Backup the configuration (Maintenance-Backup settings)
5.7. In order to propagate the new key, use a USB stick, so that you dont have to type it again and again in all PCs. I plugged a tower, two laptops, one iBook and a PSP. Without any glitch.
All the steps above, without reading the manual a lot, took less than 4 hours. But trying, testing and replugging.
Now it is time to enjoy your extended network and remember that you can extend it further, by buying another wireless adapter (the WGX102) or a RJ-45 adapter (the XE102)
Update: I bought the RJ-45 adapter and it was very easy to install, just by adding it Mac address to the list and using the same password as in the bridge.
Update 2: the speed improves definitively during the night and reach 0.9x-1.0x.