Hey guys, I'm trying to extend my router signal but am running into trouble.
First, second and third try were successful but only for a few hours. After that, I can't get it to work at all. I've been following these directions...
These instructions assume you are connecting to a WiFi access point (AP) with a working Internet connection.
[example] = example values used during my setup. Yours might be a bit different.
SOURCE-AP = the access point / router generating the wireless signal you want to repeat.
REPEATER-AP = the access point / router repeating the wireless signal, the one that we are setting up.
SOURCE-NET = the SSID (network name) of the wireless signal you want to repeat.
REPEATER-NET = the SSID (network name) of the repeated wireless signal.
Before starting, gather the following information:
- the LAN/wireless side IP address of the control interface for the SOURCE-AP [192.168.3.1]
- the subnet the SOURCE-AP is using on the LAN/wireless side. [192.168.3.x]
- the SOURCE-NET name [GROUND]
- the encryption type and password [WPA-2 PERSONAL, xxxx]
- the channel the wireless signal to be repeated is on. 
To determine the LAN/wireless IP address and subnet of the SOURCE-AP, look at the IP address and default gateway of a device directly connected to the SOURCE-AP. (Open the Network connections folder, click change adapter settings, and view status and then details in Windows).
For the channel, it is preferable to go to the SOURCE-AP and set the channel to 3 instead of "auto" so it does not change, and uses an unpopular channel likely to have less interference. If you don't control the SOURCE-AP (e.g. you are connecting to your neighbor's WiFi), you can find out what the channel is during the setup steps below.
Here we go:
1. Plug the power into the REPEATER-AP. If any settings have already been changed on the device, press and hold the reset button on the back for ten seconds until all lights are illuminated to indicate reset happening. Reset is not necessary if the unit is fresh out of the box.
2. Plug a PC into a LAN port on the REPEATER-AP with the supplied LAN patch cable. I used my laptop. Make sure the LAN adapter is set to get an IP address automatically. (Open the Network connections folder, click change adapter settings, and view properties in Windows). Make sure the LAN adapter is the only one enabled. Disable the wireless adapter.
3. Open a browser and go to http://tplinklogin.net . This gets you to the control interface of REPEATER-AP. The default username, password is admin, admin. Don't do the quick setup.
4. Click "Wireless" on the left column menu. On the Wireless Settings page that appears:
a. Under the dropdown list for "Channel", select the channel the wireless signal to be repeated is on.  If you don't know, skip this step and the unit will force you to select the correct one after the "Survey" step below.
b. Click the "Enable WDS bridging" checkbox.
c. Click "Survey". A list of SSIDs appears. Click "connect" on the one that is SOURCE-NET. [GROUND] All of the fields are automatically populated except for the password.
d. Enter the password and click Save. Wait ten seconds for the processing to finish.
e. At the top of the page beside Wireless Network Name, enter an name for REPEATER-NET [R1] and click Save.
5. Click "Wireless Security" on the left column menu. Select Personal WPA2-PSK, AES encryption and enter a password for REPEATER-NET.
6. Click "DHCP" on the left column menu. Click the DHCP disable radio button. Click Save. Ignore the reboot warning.
7. Click "Network" on the left column menu.
8. Click LAN. Change the IP address to one in the SOURCE-AP subnet that is not being used by any other device and click Save [192.168.3.200]. A reboot warning will appear. Click OK and let the unit reboot.
9. The address in the browser will magically change to the IP address you entered in the previous step. This is the new IP address for the control interface on REPEATER-AP. You will be prompted to log in again.
You should now have Internet connectivity! There is no "half hour waiting period" as others have said. Perhaps that was due to misconfiguration.
Open a new tab in your browser and go to news.google.com to verify.
Wireless devices can now connect to REPEATER-NET. Wired devices can connect to REPEATER-AP. Both get Internet access through SOURCE-AP. Ain't life grand?
It is possible that it may take some time to negotiate the wireless link between SOURCE-AP and REPEATER-AP. Wait two minutes, then refresh the news page.
If that doesn't work, power REPEATER-AP off and on. Try news.google.com again. If that doesn't work, wait two minutes, then refresh again.
If it still doesn't work, enter the LAN/wireless side IP address of the control interface for the SOURCE-AP [192.168.3.1] in a browser and hit Enter. If you see the control interface for SOURCE-AP, the wireless link is working! Try entering an Internet IP address, like http://184.108.40.206/ (one of my sites). If you see a page with content loaded, you have Internet connectivity (hooray), but your computer needs to be told a DNS server to use. In Windows, open the Network connections folder, click change adapter settings, properties, IPv4 properties, advanced, and in the Gateway area type in the IP address of the SOURCE-AP [192.168.3.1], click OK, OK, Close and try again.
But none of that should be necessary. I have written these instructions with the unit beside me, following my own instructions and it worked first time.
I have actually gone beyond these instructions to set up a chain of four of these units to provide wireless coverage from the basement to the fourth floor of a 150-year-old church with stone walls. And it worked!
P.S. Don't forget to go back in to REPEATER-AP and change the password. The menu item is hiding under System Tools on the left.
Installed it all, worked fine then crashed after two hours. Rebooted everything, worked fine for two hours, crashed.
It turned out that the units were being given an address via the DHCP protocol with a lease time of two hours.
When the lease ran out, it didn't get renewed for whatever reason.
Solution: you must go into the source-ap control panel and assign each of the units a static IP address. This fixed the problem.
It might be called "DHCP Reservations" on some brands of source-ap.
I got the directions from a comment on amazon because that's where I bought my 2nd router to use as an extender. I bought this router.
My initial router is an AT&T U-Verse router. It's used for the internet and TV service.
The only difference from the directions I used is I changed my router extender to 192.168.1.1 instead of 192.168.3.1 because my U-Verse router is 192.168.1.254. Other than that, I pretty much used all the same directions..
All and any help is appreciated. I'm open to all questions that lean towards a solution.