For those who regularly connect to a wireless WIFI network over a quite distance, being (just) out of range of the WIFI signal is a common problem. And for many reasons explained in great detail on many internet sites. For those cases where antenna & positioning gymnastics does not work or is just too much of a hassle, heres a bit of practical info of extending the range of a common WIFI signal using a wireless range extender. It's not rocket science, just a few things one should know. This story has 3 cases of extending an ordinary WIFI signal.
In this article;
Common equipment terminology used for extending the range of a WIFI signal is - Range Extender, Range Expander or (signal) Repeater / Booster. There are many on the market nowadays, some dirt cheap. In this case a Sitecom WL-130 802.11 b/g Wireless Network Range Repeater is used, purchased new for just € 19,- (27 US$) at a discounter.
The Sitecom WL-130 WiFi range extender has quite a few brainy chips inside to do it's job.
To name a few of the chips found on the Sitecom WL-130 PCB:
- Realtek RTL 8186P -WiFi access point - SOHO router Chip
- Realtek RTL 8225 - RF transceiver for WiFi standards 802.11b, and 802.11g
- Realtek RTL8201CP - 10/100M Ethernet chip
- PSC A2V64S40CTP - 8 Mbyte SDRAM chip
- Spansion S29Al016M90TF102 - 16 Mb Boot Sector FLASH memory
That's quite a bit of sophistication to repeat a simple WiFi signal.
The Sitecom WL-130 is a simple WIFI signal repeater with a down to earth instruction how to repeat a WIFI signal. It has a 12 volt DC jack and one UTP LAN connection. The WL-130 can be configured as repeater and as wireless router through it's configuration page. The 12 volt DC power specification comes in handy when there's no mains available, a simple car battery of a car can provide DC power easily. The antenna can be replaced by one with higher gain. Firmware and source-code are available at the sitecom website. Creating dedicated firmware versions from the source code is specialist work and requires compiler tools and a UNIX / LINUX machine.
In this case the WL-130 is used in it's factory installation after upgrade of the repeater firmware to the latest version.
Without going into the details of the repeater instruction in the WL-130 manual, here's a few things one should know when repeating WIFI signals.;
1) The repeater must be in range of the source signal and the one who uses the repeated WIFI signal. For WIFI networks stretched to the max, the problem usually arises with finding a power source at the repeater location. Extension cords or a (car) battery (sometimes with inverter) are common solutions to such a problem.
2) Repeating encrypted (WEP / WPA/WPA2) WIFI signals requires the repeater to know the encryption keys. The repeater has to connect to the WIFI access point to gain access to the encrypted signal to be able to repeat it.
3) When testing different encryption modes (WEP, WPA, WPA2) at the repeater / extender be sure to make the same encryption mode switch at the WIFI client side. Some WIFI connection managers have a hard time forgetting previous encryption settings for the same WIFI signal.
4) The WIFI repeater has a static IP address to be able to access the repeater configuration settings. The WIFI repeater doesn't need a DHCP dynamic IP address (it has a static address) and is therefor not seen by the DHCP server as a connecting network client.
5) The Access Point Name of the repeated signal is usually different from the AP name of the WIFI source signal. This enables the user to distinguish between the source and the repeater signal. It is possible to use the same name, however it's less easy to determine if the repeater or source signal is used when both access points are in reach.
6) The channel of the repeated WIFI signal is usually the same channel of the source. In theory the channel can be different, however it depends on the capabilities of the repeater. Switching channels while repeating a signal requires double transmitters / receivers.
7) Best chances on repeating a WIFI signal is using the same chipsets and software. Hence sticking to the brand of the wireless router broadcasting the source signal. It is possible to use mixed brands, however problems arise with more complex encryption (WPA / WPA2) and high speed network traffic.
8) The throughput capacity at the repeated WIFI access point is at least 50 % lower. The repeated signal has a repeater delay / latency because it has to be received, processed and repeated. This can be a problem for software (ie games) that generates heavy network traffic and critical response timing. More repeaters worsen this effect.
Now a few bits about the performance of the Sitecom WL-130 802.11 b/g Wireless Network Range Repeater. The task at hand is to repeat a WPA-TKIP encrypted 802.11 g WIFI signal at channel 6 created a by a Medion XG-2000 - MD40900, a simple WIFI router configured as Access Point without DHCP server. The client is an Alfa Wireless 500 mW USB 2.0 adapter with an external omni-directional antenna.
- The WPA-TKIP encryption proved difficult to repeat by the Sitecom WIL-130. Tests with 2 laptops only made the connection work for 1 after many tries. Both laptops could connect to the source AP created by the Medion MD40900 without a problem. It seemed, connecting to the repeater AP was successful, however no IP address was handed out by the DHCP router.
Multiple tries have the same result, the repeated signal with WPA-TKIP encryption doesn't work well enough. It seems there is a timing issue, ruining proper communications.
- Switching to simple WEP - 64 bits was immediately successful. Connectivity in the extended wireless range worked ok for e-mail and surfing. No heavy download tests were done on either side of the repeater.
- Searching for the optimal repeater location was a quest. With power extension cords the repeater location was in a small shed, luckily with a 220 Volt mains connection.
With small price paid for the Sitecom WL-130 in mind, it does it's job however not with the encryption technique (WPA) originally started of with. Network security might be at risk in an urban area, however in this case the risk is small, the rural area is lightly populated. The administration / configuration interface of the network extender is simple. However it has 1 advanced settings page, requiring deep knowledge of WIFI 802.1. If the WL-130 would be a more expensive range extender, expectations would certainly be higher.
A few months later the task to repeat a WIFI THOMSON SpeedTouch 780 signal now encrypted with WPA2-PSK- AES. The THOMSON SpeedTouch 780 with software revision 220.127.116.11 was located at about 300 meters (980 feet) without line of sight inside a building. At this distance the WIFI signal was visible but too weak for speeds above 1Mbps. The client is an Alpha Wireless 500 mW USB 2.0 adapter with an external omni-directional antenna. The Sitecom WL-130 was connected to a 12 volt car battery because there was no AC mains available at the repeater location.
The Sitecom WL-130 range extender / expander / repeater connected to a 12 volt car battery.
- At first all 3 WPA security modes failed using WPA-TKIP, WPA2-AES and WPA2-Mixed at the WL-130 repeater. The Alpha Wireless USB adapter couldn't obtain an IP address.
- Because of WPA security switching at the repeater, it seemed the Alpha Wireless 500 mW USB 2.0 adapter didn't follow the switching correctly. At each new attempt the Wireless profile at the Alpha Wireless 500 mW USB 2.0 adapter was deleted. The WPA key was entered each time.
- The Sitecom WL-130 succeeded in repeating the WIFI signal in WPA2-AES mode.
The new repeated WIFI network speed was 11 Mbps. The repater was located near the THOMSON SpeedTouch 780at about 50 meters (160 feet) distance. The repeater was in line of sight of the Alpha Wireless 500 mW USB 2.0 adapter.
The sitecom WL-130 managed to repeat a WIFI signal from a Linksys Wireless WAG54G2 in WPA2-AES mode. Same as in case 2, WPA-TKIP and WPA2-Mixed didn't work. Both devices have the latest firmware version. This case is tested / reported by Tariq. Thanks for that!
The WL-130 worked continuously for more than 5 months. It has doubled the network range in a forest and urban area with no line of sight. In one case network security had to be degraded to WEP, which is unacceptable for a urban area.