Saturday, October 23, 2010

Cantenna

I've found this little program called Inssider 2.0 to monitor the strength of the wireless signal.
Here's what the connection has come down to:

As you can see it hovers around -90, which means: you can't have a stable connection. I know that at around -75 it is good enough to actually use it. So naturally I thought about options to gain those 15-20 dB.
I found out that you don't have to spend fuckloads of money to improve the sending or receiving power of your system. With a bit of knowledge and the right tools you can build your own antennas.
Well, I can't do anything to the source of my signal, because it is not mine. Therefore all I can do is try to enhance the receiving end by building my own new antenna. But how to connect it to my laptop?
Since I am no electronic specialist and don't own the right equipment, opening up my computer and fucking around with the built-in antenna simply is no option. Therefore I decided to get my hands on an USB external wireless dongle.

I figured if I can get a gain of 15 using the dongle, everything'd be just fine.

So I went to the store to buy one (I knew they had exactly one available), but in the end I didn't have to purchase it, because luckily one of my co-workers had one sitting around unused, and he gave it to me for free.
Yay! So went to the canned-food aisle and bought myself a can of ravioli (the only bad side of this little project, I had to eat them). Then I went home and tried out my new free USB device, an old Trendnet tew-624.

Thing is: I hooked it up to my computer and the thing didn't even pick up a signal. It is actually weaker than the antennas that are already built into my computers. Using the dongle as connecting device I had to walk outside to get the -90.
That sucked.

The whole project had instantly become useless, because even if I managed to get my 15 dB of gain, I would just end up where I was before.

But then again, I had already bought and eaten the fucking ravioli, so by god, I wouldn't not refrain from building my antenna!

So I sat down with my swiss army knife and assembled this device:


So this is a pretty directional home-made antenna. Using it I managed to get about -90 inside. So it actually worked! I thought about setting it up outside, but because of a number of reasons like cable-lenght, window-situation, outside-temperature, possibility of theft etc. I decided against it.

Instead I opted to try different antennas first, and also to enhance the performance of this thing.
I looked around in the apartment for things to use to collect microwaves, and in the bedroom I found a metal lampshade. Then I made this:


Unfortunately this device didn't work at all. So I took it apart and instead built this thing, an attempt to create a spherical reflector, some kind of two-dimensional parabolic dish, if you will (I wish I had an old satellite dish).


I used tin foil and string, but it was very hard to find the right spot for the usb stick. I couldn't find any means to create a stable construction, so that's why I abandoned this one and went to build this instead:


Well, I got a flicker out of that one, it would pop up every once in a while somewhere at -96 or something. I decided to combine it with my initial successful cantenna:


But this didn't do anything but bad to overall performance. So I disassembled everything and felt satisfied enough that I managed to build a working cantenna (and to waste a lot of aluminium foil and duct tape). No practical use in the end, but it was fun anyway.

Now, if I had an old satellite dish, I could combine it with the cantenna and aim it directly at the source of the signal, that should get me another 10 dB, I think. Maybe I'll find one somewhere.

By the way, I'm writing this on my old laptop from the other building. They've started to build the roof on the building inbetween. Our apartment is now completely cut off.

2 comments:

Anonymous said...

At one point while reading this, Thekla came suddenly into the room to check on me; she thought I was crying. Apparently, when I laugh quietly (so as not to disturb the baby) I sound like I'm crying. I was unaware of this. Anyway, she read it too and also started to laugh so loud that quiet laughing became necessary. Dude, we bond over your blog :-) Danke.

It has to be said that in this post the pictures are awesome; they really enhance the story. I like your stories :-)

-Anne

Brato said...

thanks.