jueves, 19 de febrero de 2015

DIY Directional Wifi Antenna Booster

While living in Thailand, I rented an apartment where the internet wasn’t provided thinking it would be easy to get on my own.  Boy was I wrong.  Internet was around $150 to start, $100 a month, required a 12 month contract, and you needed a Thai ID (back in 2007), so I went looking for other options. I came across this site and decided to build my own wifi antenna booster out of a chinese spoon, so I could then get wifi from the bigmac shop down the street for free.
The parts were relatively cheap ($50 in all), and most of that expense was in the usb dongle.  My parts list included:
usb dongle
baby bottle (it rains HARD in the tropics)
usb cable (with amplifier if over three feet)
wire cutters
electrical tape
silicone glue
craft plastic mesh(to center in the baby bottle)
asian parabolic wire spoon
The hardest part of the build is figuring the out the exact the placement of the antena in the spoon.  First you need to find the exact spot of the antenna in the dongle so you can place it right at the focal point of the spoon( I think I actually took off the plastic case to solve this mystery.)  Next you need to find the focal point of the spoon by using Cartesian equation(f=D^2/(16c)) or the square of the diameter divided by 16 times the depth of the spoon. The rest is easy, cut a hole the size of the bottle, put the usb cable through the nipple of the bottle till the distance is right at the focal point and tape the nipple to the wire, and put it all together.  I ended up taping it to my mop handle and leaving it on my balcony railing.
and the finished product:
It worked amazingly, I was able to not only get Wifi from the burger spot down the road, but I was also able to get signals from the high rise 1km away.  Here is a pic from in front of my building to illustrate how far it was to the end of the street where the signal was coming from:
Screen Shot 2013-02-01 at 7.17.13 PM