How to boost and extend Wifi network coverage

An increasing number of people in the Maldives have adopted the wireless networking technology, Wifi, as their preferred mode of computer networking to connect together the computers at office and home environments. The wire-less nature of Wifi allows people to easily and cheaply setup a network that covers their home (and neighbours) for gaming and sharing internet. Sadly, the rich presence of metal constructs (iron rods in buildings, tin roofing etc), tend to scatter and attenuate the signal considerably.

One of the best ways to increase the signal and extend coverage is to use a Wifi antenna. Nevertheless, Wifi antennas do not come cheap and are not usually available in the shops in Male'. I am an avid DIYer and in my experience, constructing a Wifi antenna yourself is cheap and yields results as good as most commercial products.

There are many designs of antennas that are suitable for Wifi use. A Cantenna is a type of antenna for Wifi use that became quite famous a couple of years ago and remains a favourite among the DIY community. My favourite, however, is the Bi-Quad. It is compact and gives about 12 dBi gain in signal. A bi-quad can be made using just a single, small piece of copper plate/sheet and copper rod/wiring - both of which are easily obtained from several hardware stores in Male'. I bought them for less than MRF 100/- total in September this year. Assembling the antenna would require a soldering iron and would take about half an hour at most. You may connect the antenna directly to a wire or have a connector on the antenna so that you can use any commercial pigtail connector to attach it to the wifi card or access point. Remember to double check all dimensions and connections before connecting the final product to the wifi gear. Use NetStumbler to check the signal strength change.

There are many resources on the net detailing bi-quad antenna construction for the 2.4Ghz range. Check out the following links if you are interested in building one:

Have fun ;-)

1ft x 0.5ft copper sheet

Copper rods and a completed bi-quad loop

Open routers at Dhiraagu hotspots?

Dhiraagu Wifi hotspot is something I had mentioned in an earlier post, however, I hadn't got a chance to experience the service on my laptop till recently. The opportunity popped up when my flight to UK got delayed and had to kill some time at the food outlet at the airport. My laptop readily found the "Dhiraagu Wireless Hotspot" SSID and a stable connection was established. The service was quite decent and I could browse and download in comfort and with speed. It certainly was a luxury that quite a few people would happily pay for.

As ever, curiosity got the better of me and I decided to peek a look at how the service was operating. Access controlled wifi hotspots usually operate by allowing unprotected (that is WEP/WPA free) access to the wireless network and then authenticating the client with a central access controller. The client needs to open a web page, any page, upon which the browser gets redirected to a service login page where the user is prompted to enter the login details that grant them access to the internet thereafter. The login mechanism also serves as a means to facilitate billing.

The Dhiraagu system operates in a similar manner. Below is the screen that we are shown upon connecting. Notice that they are giving the username/password to login with in the current free access promotion they are running.

The browser flickers as the system guides it through a series of links to complete the authentication. Looking at the URLs that the browser hit through, I picked one "interesting" looking IP...

And voila comes the web administration interface for a Cisco router - the equipment that Dhiraagu is using to provide the Wifi hotspot service!

The router apparently is configured without any administration password and the act of going to the router's IP address provided unfettered access to the wifi router and hence control over the wifi hotspot service.

I wonder if this is true for all the rest of Dhiraagu hotspots splattered across Male'. The service is great, BUT is this how the system was deployed? This configuration of the wifi hotspot lets anyone command control over the router and facilitates all kinds of mischief!


Much of the Male' populace goes out in the streets on vehicles as the time approaches midnight. This occurs without fail every night, much similar to the night creatures that crawl out when the sun drops and the moon rises. Now, this may happen for a variety of reasons but I am not going onto a discourse on the wierd lives led by Male' residents; not this time anyway.

Anyway, tonight I too came out of my shell and roamed the streets of Male' on the back of a motorbike with my kid brother in the driving seat. On the backseat, yes, because I had decided to take the risk of looking totally ridiculous carrying a laptop and an antenna which was hooked onto my 802.11 b/g card. It wasn't the least bit easy feat to pull off, especially when I had to carry the laptop on my lap and the antenna with one of my hands with the rest of the useless gear inside my laptop backpack strapped onto my back!

Yes. This is what you call wardriving, or maybe warriding in this case. I chose not to go in a car because while I could have been sitting much more comfortably inside a car, the narrow, crowded streets of Male' ain't too welcoming to a wardriver driving at 15mph. Additionally, I was using a Cantenna as my antenna which happens to be directional thus limiting angles and maneouvarability inside a car.

The Gear:
+ Laptop with MS Windows 2003 Server.
+ ORiNOCO Gold 802.11 b/g PCMCIA card.
+ 12 dBi commercial Cantenna.
+ NetStumbler 0.40

While I did not cover the entire island, I presume I did cover much of the business and government office areas. We went once around Male' - starting the scan near the Maldives Ports Authority, travelling on Boduthakurufaanu Magu till Lonuziyaaraiy "kolhu" and then travelling down Ameenee Magu uptil the turfed football field at "ohggaa" stadium where we made little detours to cover Kalhuthuhkalaa Koshi and the new Faculty of Health Sciences building and SHE building, then continuing on Boduthakurufaanu Magu going past Indira Gandhi Memorial Hospital, Maldives Centre for Social Education and ending near the new STO building. The scan continued till I reached home.

The little trip picked up 73 Access Points and 4 Peer-to-Peer networks. Of this total, half of them had encryption off! Majority of the networks seemed to be "b" networks and the prevailing brand of APs happen to D-Link. There were 11 APs with the default SSIDs. Most of the WIFI networks bore the name of the office or home it belonged to, thus making it easily identifiable.

Looking at the results, it is good to see that atleast half of the networks are protected by some form of encryption. The fewer number of SSIDs with default names suggest that in most cases someone atleast took to the task of properly setting up the WIFI network. How secure these networks really are, however, remains to be tested. I intend to do a more thorough wifi investigation around Male' soon, with Kismet (under Linux) and an omni directional antenna. Check here laters for updates on that.

By the way, here is the NetStumbler file generated by this wardriving session.