How to implement a WiFi range extender for $20

A volunteer project to set up WiFi in a 150-year-old building with stone walls that I did recently required repeaters, also known as range extenders.

I ended up writing detailed instructions to get a popular WiFi access point / router on Amazon working as a repeater… and thought you might find this useful to extend WiFi coverage in your home or small office.

teracom-tutorial-wifi-repeater

Even if you don’t need to extend your WiFi coverage, understanding the configuration, including the IP addresses, DHCP, subnets and all the other items covered in this tutorial is career-enhancing knowledge.

The IP addressing story including DHCP is covered in
Online Course 2213 “IP Networks, Routers and Addresses”
(part of the CTNS Certification Package), as well as

Instructor-Led Course 101, the Telecom, Datacom and Networking for Non-Engineers textbook, and DVD-Video Course V4 Understanding Networking 1.

The requirement was to provide WiFi coverage in a 150-year old building with thick stone walls. The Internet connection (DSL) was in the basement, and coverage was required to the fourth floor.

We initially looked at pulling a cable to the fourth floor, but the stone walls made wireless a no-brainer.

The WiFi signal produced by the ISP’s Customer Edge device, which contains the DSL modem, a router, switch and WiFi Access Point, did not reach very far.

So WiFi repeaters, sometimes called Range extenders would be required. This had to be implemented with encryption of data over the air for information security.

Special-purpose range extenders can cost $300 each. After a bit of research, I bought these $20 units on Amazon.

They support “300 Mb/s” 802.11n, and most importantly, implement the Wireless Distribution Service (WDS) with WPA2 airlink encryption, which is needed for the repeater function with security.

Here is the product link on Amazon.   I don’t get a commission.

The instructions weren’t very complete, so I looked at the product’s Q&A section on Amazon and found instructions.
But those instructions turned out to be not quite right. And being an Engineer, I couldn’t help but proposing correct instructions…

These instructions assume you are connecting the WiFi access point / router pictured, TP-LINK model TL-WR841N, to any WiFi with a working Internet connection.

teracom-tutorial-wifi-repeater

Abbreviations:
[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. This is often supplied by your ISP.
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.
GUI = Graphical User Interface.
This is the access point / router’s control panel.

Before starting, gather the following information:
– The LAN/wireless side IP address of the SOURCE-AP GUI. [192.168.3.1]
– The username and password for the SOURCE-AP GUI.
[admin, admin]
– 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. [3]

If you don’t know the channel, you can find out during the setup below. However, it is preferable to log in to the SOURCE-AP GUI and set the channel to 3 instead of “auto” so it does not change, and uses an unpopular channel likely to have less interference.

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). The value in the default gateway field is the IP address of the SOURCE-AP GUI. The part of the address common to the default gateway and the device is the subnet ID.

Do this setup and get it working somewhere comfortable near the SOURCE-AP. Once it’s working, you can place the repeater anywhere near an electrical outlet.

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 GUI of REPEATER-AP, initially 192.168.0.1. 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. [3] 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 a 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 GUI on REPEATER-AP. You will be prompted to log in again. The status screen will appear. Under Network, click the WAN MAC menu item on the left.

You should also now have Internet through REPEATER-AP!
Open  news.google.com in a new tab in your browser 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?

10. To avoid problems with dynamic addresses and timeouts, make the IP address of REPEATER-AP static.
Open a new tab in your browser. Enter the address of the SOURCE-AP GUI [192.168.3.1] and log in. Find the screen that lets you assign static IP addresses. The SOURCE-AP could be any brand of device; it is often supplied by your ISP. The function might be called “DHCP reservations” or “IP address reservation”. Make a new entry, with the WAN MAC address displayed in the REPEATER-AP GUI and the REPEATER-AP IP address you entered in Step 8.

I actually 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 building with stone walls.  And it worked!

Good luck!

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.


Notice required by the legal department: This information is provided as general background information only. Design and implementation of a communication system requires professional advice to identify and resolve issues specific to that particular system, including but not limited to performance, availability and security issues. Additionally, while we have strived to be as accurate as possible, we make no representation or warranty that the information provided is 100% accurate. This information is not to be relied upon as professional advice, nor is it to be used as the basis of a design. Users of this information agree to hold the author and Teracom Training Institute Ltd. harmless from any liability or damages. Acceptance and use of this information shall constitute indication of your agreement to these conditions.

16 thoughts on “How to implement a WiFi range extender for $20”

  1. Hi Eric – thank you for the detailed instructions.

    What kind of throughput are you getting at the repeater?

    I setup a similar configuration with some older 802.11g Linksys WAP and am lucky if I get 10 megabit through the link.

    Thank you again.

  2. You’re welcome. It’s important to note that all WiFi / 802.11 is “half-duplex”, or more accurately, alternating.

    Only one device using the same SSID can transmit at a time on the radio channel.

    In normal operation communicating to a server on the Internet via an AP, your computer transmits, then there is a silent period, then the AP transmits and repeat.

    This means the actual throughput measured using speedtest.net is going to be WAY less than what the marketing department wrote on the package.

    The old 802.11b “11 Mb/s” systems achieve closer to 1 Mb/s in reality because of this.

    It also means the repeater function is going to further cut the maximum throughput by a little worse than 50%, since everything it hears is transmitted again, and $20 units like this one use all of their radio transmission capability at once on one channel.

    The way I have suggested to set it up, it would hear something on SOURCE-NET then afterwards repeat it on REPEATER-NET on the same channel.

    On an old 802.11b or g system, that would be a problem. On these units with “300 Mb/s” written on the package, it’s going to be much less of a problem… you’re going to be getting around 100 Mb/s in reality, which is more than your Internet connection, so not a problem.

    I don’t have a tool to test the actual throughput of the wireless link, I only have speedtest.net that tests the link between my computer and a server on the Internet.

    Running speedtest on a computer hard-wired to my DSL modem, I got around 15 Mb/s downloading. Running speedtest on a computer connected to the FOURTH of these units (a chain of four repeaters in series), I got around 11 Mb/s downloading.

    I haven’t run the speedtest through just one of these units set up as a repeater, but the evidence suggests there would be a slowdown of maybe 1 Mb/s through each repeater due to the overhead.

    Note that you can get around the 50% performance penalty due to repeating on the same channel with a $$$ repeater that has two independent radios in it, that hears a signal on one channel and repeats it on a different radio channel.

    Or… use two $20 units. Unit 1 listens on SOURCE-NET and does not repeat anything wirelessly. A LAN patch cable connects a LAN jack on Unit 1 to the WAN jack on Unit 2. Unit 2 generates REPEATER-NET on a different radio channel.

    But that’s a different exercise 😉

  3. When I get to step 9 here, and I reboot the router, I get a “page cannot be displayed.” and I can’t access the router any more at the new or old address, and I can no longer connect the either the new or old router wirelessly.
    Only turning the new router off and power cycling the old one allows be to get back online. Weird.

  4. I imagine the problem is with the IP address of either REPEATER-AP, your PC, or both, after the REPEATER-AP reboots. There are quite a few things that could cause these to be incorrect.

    #1 would be that you have both the LAN adapter and the Wireless adapter on your PC enabled in Windows, causing your PC to be misconfigured.

    Make sure you have only either the LAN port or the Wireless adapter enabled on your PC at any one time. Use Control Panel > Network Connections > Change adapter settings > Disable this device. Disable both then enable one.

    If that is not the problem, the key to determining the problem is item 4 below.

    Things to check:
    1. To ensure it is not PC or browser weirdness, empty your browser cache and close the browser. In Windows, click Start and search for run, then in the run box enter ipconfig /flushdns and hit enter.

    2. Unplug and replug the LAN cable to force DHCP to run.

    3. Try going to http://tplinklogin.net. Try going to the numeric address you entered in Step 8.

    4. Look at your PC’s LAN adapter status details and see what IP address it is reporting. Is it in the SOURCE-AP subnet? Is it reporting the default gateway as the IP address of the GUI for the SOURCE-AP [192.168.3.1]?

    If not, the DHCP from SOURCE-AP didn’t work.
    a) That could be because the radio link is not working: verify the SOURCE-NET password and re-test with another device like your cellphone to be sure you have the correct password.
    b) The SOURCE-AP DHCP server is disabled. Log on to SOURCE-AP and make sure its DHCP server is on.
    c) Your computer is not set to get an IP address automatically.

    There could also be a problem with the IP address you enter in step 8.
    d) The IP address you entered in Step 8 is not in the SOURCE-AP subnet.
    e) You used an address that is already assigned to another machine for Step 8.
    Log on to the SOURCE-AP and note the range of addresses SOURCE-AP DHCP server is handing out. Verify the attached devices and the addresses they have been assigned.
    Pick another address that is in the range but has not been assigned [192.168.3.150]. Use that in Step 8.

    If that doesn’t change anything, change your PC so its LAN adapter uses a specific IP address in the correct subnet. Choose an address similar to the one for Step 8. [192.168.3.151].

    Enter the address of the LAN/wireless side IP address of the GUI for the SOURCE-AP [192.168.3.1] as the default gateway. Try to go to the LAN/wireless side IP address of the GUI for the SOURCE-AP [192.168.3.1]. Try going to the IP address you entered in Step 8.

    Good luck!

  5. Did you update the WRT update and v9 people mentioned? I’m wondering if I need to do that in order to make the bridge work?

    I have old routers and I have them each on their own subnet, so right now i have 3 SSIDs in my house. They are too old to get bridging to work.. so I bought two of these to try out so I have a single SSID in my house.

    thanks.

    1. No need to update the firmware, it worked fine out of the box. Besides, the instructions I gave use the installed firmware’s menus, which would go away with an update…

  6. sorry, one other question. I have some internet ports through my house and I was using my other routers as a hub as well, so I have each routers main ehternet port connecting thru a cat5 cable to my main router.

    I get that as a repeater I don’t need the new router to connect to my main router, but do I need to do that in order for the wall jacks to continue to work?

    Thus right now:
    Main router (SID 1hw11) – ethernet to Verizon
    ports 1 and,2 run to ethernet port of my other 2 routers which have their own SSID (1hw11b and c).

    On those other 2 routers, some of the ports also run to other wall jacks.

    New setup – nothing into the new router ethernet ports once they are setup as repeaters… or should I keep the cable in the ethernet ports- as the routers are 50 feet from the source I think I need that?

    1. You can plug patch cables from a port on SOURCE-AP, or REPEATER-AP once it is working, to a jack on the wall, which will then provide a working LAN connection at the jack connected to the other end of the in-wall cable if you want.

      Note that if there is an in-wall cable that goes from where your SOURCE-AP is to where you want to put REPEATER-AP, there is no need to set up REPEATER-AP with a wireless connection to SOURCE-AP. Set REPEATER-AP so it has a LAN address in the same subnet as SOURCE-AP, its DHCP server to off, and its WAN connection to disabled, then plug a LAN port (not the WAN port) on the REPEATER-AP to a LAN port on SOURCE-AP via patch cords and the in-wall cable.

      REPEATER-AP (both hardware ports on it and the wireless) is now acting just as a LAN switch. Any devices that connect to REPEATER-AP’s wireless or hardware port will talk through the in-wall cable to SOURCE-AP’s DHCP server to get an IP address and everything will be in the same subnet. This is actually the desired configuration… since the wire is two-way simultaneous and the wireless is two-way alternating, a wired connection between SOURCE-AP and REPEATER-AP will be more than twice as fast as a wireless connection between the SOURCE-AP and REPEATER-AP.

      Cheers

      EC

      1. It worked, I was able to replace my existing B and C routers, and the download speed went from 6mbps to over 30.

        One thing, I wanted to reconnect to change the admin pwd.

        I had set each ones IP to 192.168.0.200 and .201, but I cannot reconnect to them no matter what I try. Ideas?

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