top-quark.blog
Signal boost
Mon, 05/22/2006, 00:43I'm pretty used to bad wireless network reception in my section of the house. My Qwest-suppied Actiontec GT701-WG, for lack of more suitable words, is pretty damn shitty. It's got an omnidirectional stubby stick antenna, with no provisions for an external connection. Compound that with it being across the house on another floor, and it's a pretty sad situation for most of my machines. Seeing as the modem is situated on one extreme of my house, having directionality would help a lot.
Now, normally, I'd just drill the casing on the Actiontec, and attach a socket for an external antenna (eg., Pringles cantenna), but this modem's such a piece of crap that we'd be insane to actually BUY one. Consequently, we're actually renting it from Qwest. So my usual approach is out.
Came across this site today, and noticed a very elegant solution in the lower-left - the "Flatenna", from a company called "Tritium". It's a nice idea, but it's expensive (~$15 shipped, IIRC?), too small, and looks a bit too flimsy for me. So, I'm gonna DIY my own.
The biggest issue is getting a good parabola. I could just bend some stuff around, which would work OK, but I intend to make a couple of these, for different purposes, and I have enough interests that parabolas are a frequently-recurring useful shape. For template-type things, my usual approach is to make something in AutoCAD, then print it out. Oddly enough, AutoCAD doesn't have a parabola generating function.
I just came off a project heavily involving graphics generation in Java, though, so I thought I'd put together my own parabola generator. The issue is that the images I was generating are actual images, like jpg, tiff, png, etc. When printed, these don't typically have a consistent scaling or centering, and if they do, they're not controllable. A tool that does have these abilities, though, is the Adobe PDF reader.
Using a PDF Java library called "iText" (cringe), I wrote up some code to generate a PDF of a parabola from coded values, with the focal point marked. Source code, if you're inclined, is here. The pdf I generated to make my pattern is here.
From the parabola trace, I made some reflector holders out of cardboard, and a reflector from cardboard, covered in metal furnace tape. If you're ghetto enough (and aren't we all?), aluminum foil will work in a snap. I used two holders to support the reflector, and drilled a hole through the focal points, for the antenna.
So how's it work? Pretty damn well.
As reported by the driver software, the farthest computer from the station went from -67 to -57 "arbitrary units" (yes, it actually says "arbitrary units"), which is enough to make net connections very stable. As pointed out by a couple people, those "arbitrary units" look a LOT like decibels, which is fairly typical for wireless cards. My only worry is that they're offset somehow, but assuming that the underlying unit actually is decibels, the 10dB difference translates to an order of magnitude difference in signal strength.
Another fringe benefit is that I can no longer lock onto the signal from outside my house, on the other side of the reflector - a significant security boost.
Comments about "Signal boost" :
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-left by kythri ( http://www.kythri.net)
Hmm.. interesting fix.. I am currently in the same quandry, as the "Wonderful" Qwest-supplied Action(less)tec modem upstaris does nto want to communicate with my wireless card downstairs. Lame, eh? Now, I'm not quite to the point of makig a shiny curvy parabolic thingamahingy you made.. Im thinking about simply drilling a hole in the floor, and dropping a few cables down, suspending the modem beneeth the substrate of the floor itself.. Ill let ya know how it works. If, however, it does not (There is still a gigantic concrete wall in the way.. the house builder was a moron..) would you mind suggesting a few ways to drill into the case and add an external antenna as you had mentioned? I, unlike the lucky ones, *OWN* the modem now..
-left by Pierced ( Pierced@PierceThePlanet.com)
Drilling a hole in the floor sounds a little more involved to me. With that much concrete, I'm not sure even an external antenna will help you. That said, the usual procedure is to first open the case up, then look at the antenna's attachment scheme. If you solder in an appropriate RF connector, in place of the stock antenna, you can usually get away with not drilling. Just be aware that you need a designed antenna - experimented designs can affect the SWR of your system, potentially damaging the wireless subsystems, or the whole modem. Which, to be honest, might actually be an improvement on these turds.
-left by TQ Admin ( )