U have to consider also not only the signal but the fluctuations can appear(up and down-stability,interferences) and from my experience with wifi antennas the best is pointed 2.4ghz and not that way of boosting signal witch it looks like a pointed antenna but with a wifi usb receiver(OMG).
I've been using something similar(pointed antenna) a couple of years ago when wifi was still weak and not on everybody's use.I'm one of the first makers in some wifi networks groups,building,testing,wasting money on this and i found it easy now but a challenge when u want to build an pointed antenna signal who suppose to beat 70 kms.
So far my best was around 50 kms or so and i use now in my car also my internet connection from home,with a pointed routing black box.
Its good when u dont want to spend alot of money for a service u dont really like the performance of.
Also in the past i was using an 18 db antenna build from a plastic pipe with copper segments for internet boost,but the suck part was that i had to stop my car always when i wanted to go online(now the things have changed).
Now i still think thats the best way to boost ure signal.To make ure own antenna and not the video way.Just cut 24 copper segments or use a satelite cable cuz its cheaper,get a plastic pipe,some silicon rubber and a connector,some free time and ambition and u have ure boost antenna ready to go(if u use a cable between pc and antenna ,u might loose some dbs so the performance can go to a big 0,depending on distance,also the cable type).U can use it if u have a wifi card instead of that little antenna provided by the manufacturer or just in case instead of usb.
Ok,if u are interessed to build one,i'll be more then happy to give u some schematics and informations,links,pictures ,explications how to,etc.
And...belive me,thats worth every effort,not like that video u posted
