In this article I'll (hopefully) be able to help some of you be able to build a homemade device that you can connect to your laptop or desktop and greatly improve your computers ability to recieve a wifi signal. The techniques, parts, and tools required for this are for the most part stuff that most of you will already have handy in a drawer or stuck in a closet somewhere. For example, I'll show you step by step how I built one for the purposes of this tutorial using nothing but pieces of random stuff I gathered from my house and garage and didn't have to spend anything at all.
There are 2 sections to this article. The first half is about the history, specifications and tools/software that is used to build the different kinds of antennas that you may find from the cheapest "Cantenna" from a pringles can to the huge parabolic dish recievers you see on buildings.
For those of you who prefer to skip to the second part which is the step by step guide to building an antenna, you can use ctl+f and search for one of the chapters to skip there automatically.
TABLE OF CONTENTS:
Section A: History and Technical Details
PRE001 - Preface
A100 - Overview
A200 - Types of Antennas IMPORTANT
A201 - "Cantenna"
A202 - "Backfire Antenna"
A203 - "Biquad Antenna"
A204 - "Parabolic Antenna"
A205 - "Yagi Antenna"
A206 - "Helical Antenna"
A300 - List of helpfull websites and tools
Section B: Build A Cheap Antenna
B100 - Think like MacGyver!
B200 - Parts You'll Need
B300 - Assembly
B400 - Tuning & Testing
END001- Conclusion
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PRE001 - PREFACE
Preface:
I want to be clear about the scope of this article before we dive in. When talking about this subject and doing research on the technical details you are going to have to keep something in mind. The math, physics, and signal analysis equations that are used in one article about boosting wifi signal can be (and often is) completely and totaly different than the ones used in another article talking about the exact same subject. The difference is that one is talking about boosting your home network signal (putting antennas at both ends of the connection) and another is talking about boosting your reception ability (antenna only on the computer end of the connection NOT the router). This article is meant to be about the second type so that you can use a (sometimes portable) antenna to access far away networks, or even networks while you're in a vehicle or business and not at your normal connection spot. Most of you can probably see why this would come in very handy at times.
A100 - OVERVIEW
Some of you probably already know that there isn't just one kind of antenna out there. Actually there are more than a dozen different varieties popular enough to mention here and I'll go into several of the most common types and what their uses are in this section. There is no one "BEST" style of antenna since different designs and materials each have their own strengths and weaknesses in one area or another. For instance, the parabolic (dish type) antennas generally get the best reception signal out of the group, but they're pretty much completely stationary because of their size, shape, and overall awkwardness if moved from their mounting position. For this reason, some people like myself often have more than one type of wifi antenna on hand.
I personally have 3 homemade units that I actively use at any given time. One for my house mounted outside that stays stationary and gives me connection options to AP's all around the nighborhood. This is a dish type antenna that i made from an old Dish Network Satellite by modifying the pickup attached to the end of the arm and connecting it to a wifi antenna connector on my computer.
The second one is inside my house, and also for the most part stationary although its small and mobile if i would ever need to take it, that recieves the signals from all my wireless devices and keeps them linked into my home monitoring and entertainment systems. This is a 6 foot yagi type setup that i use in conjunction with my router to make sure I have full signal anywhere on my property. I stream a 16 channel DVR security system over my connection so I always hate when I have to deal with weak connections and jumpy video/audio.
The last is a compact 3 foot yagi antenna that i keep in my truck that has a magnet on the base so i can stick it to the roof whenever i want to get online while i'm not at home. If I ever had a reason to access a connection that has absolutely no connection to me then this would be the route I would use since I could park in an apartment building and using the yagi pick up dozens of networks. They're really cheap (most of the parts you will probably already have in a junk drawer or in the corner of a garage), quickly assembled, and easy to make(although some of them can be tedious when it comes to the measurements and specifications...you don't want to get in a hurry)!
A200 - TYPES OF ANTENNASList of helpfull websites and tools
There are 2 general "Types" of Antenna and for each type there are dozens of different designs. You have the "Omni-Directional" which are units that transmit/recieve a signal in a 360 degree pattern so you won't have as much of an issue zeroing in on the signal but generally these units have less Gain.
The second type is "Directional" which concentrates the signal in/from 1 direction which means higher Gain, but it has to be pointed the right way or you won't get a signal at all. THIS IS THE IMPORTANT PART TO REMEMBER: The best Gain is the whole point! Notice what i said...BEST gain not HIGHER gain. sometimes its better to go with wider signal area coverage rather than stronger pinpoint connection...Like when your target is partially obstructed this is the more common type of signal transmission that you will see.
A201 - "Cantenna"
The most familiar variant on the home made antennas is the cantenna. Widely popular mainly because its extremly inexpensive and simple to construct. As the name suggests, creating one of these usually means taking a "CAN" preferrably one of a certain size/shape ratio and attaching a couple pieces of hardware to make a waveguide. there are some popular variants on these noteably the "Pringles Cantenna" and the "Coffee Cantenna". Just a tip: I've long since graduated from using a cantenna as a primary signal reciever, however they work incredibly well when you join them with a parabolic antenna and mount one at the focal point where your reciever hardware is.
A202 - "Backfire Antenna"
To be completely honest I don't know much about this type. I've built dozens of every other design but for whatever reason I've never attempted to evaluate one of these. I thought it was worth mentioning since i've heard people praise them highly because of their great performance capability relative to their size (radiolabs touts them at 15 dBi and 10 inches wide. GREAT gain/size ratio. Parts to make these are usually just as likely to be lying around your house as any other unit here. They're not rare parts per se but you may not have everything to spare all at once. Also, its odd shape and dimensions put a hinder on the units range of where it can be placed.
A203 - "Biquad Antenna"
These look like a copper Bowtie perfectly suspended over a copper plate. Biquads are generally used as the pickup or reciever point on another type of Antenna. There is a coax cable fed throught the copper plate and soldered carefully to specific locations on the biquad to maintain the correct flow and then the coax cable runs to whatever wifi card you're attaching the antenna to. Most commonly used at the focal point of a Parabolic Setup just like the cantenna.
A204 - "Parabolic Antenna"
This unit is the powerhouse with massive juice, massive power, the most sturdy. and once its mounted you usually won't need to mess with it much after that. Drawbacks are due to its massive size. Its much heavier than anything else here. Really difficult to mount the first time, especially if you're alone. Once you've got the damn thing mounted you have to tune it in to a connection. Remember earlier when i said BEST gain and not HIGHEST gain? the crew at radiolabs have the best explaination for that: "...As the gain of an antenna increases, the antenna’s radiation pattern decreases until you have a very little window to point or aim your dish correctly...". You can read the entire WiFi Antenna's article from radiolabs http://www.radiolabs.com/Articles/wifi-antenna.html
A205 - "Yagi Antenna"
These are my personal favorites because if you take your TIME assembling them initially they have great range, strong signals, and although measurements and angles needto be quite precise they're really simple to assemble. I have 2 of these on hand usually. One larger one that helps run my wireless cameras, computers, and entertainment system at my house, and a small one about 18 inches long with a usb wifi adapter that I keep in my trunk just in case i need it on the road for any reason. measurements and assembly are TEDIOUS. not as durable as they really should be unless you give an extra effort during construction. although the parts arent exactly as hard to find as Plutonium, they're still a bit more rare to have lying around the house than some of the other designs.
A206 - "Helical Antenna"
Probably number 3 in my list of preferences. Looks like a corkscrew glued to a plate sitting on its side. Cirucular polarity. because of what its made out of you'll have an easier time here with durability. Is meant to mount higher than normal. The ones that I've tested did better when mounted half again as high as other types running the same tests.
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NOTE: There are many more types than what I have mentioned (pole, whip, dipole, strap, panel, grid, etc etc) but I'm giving information based upon what I have personally tested and used, not on information given by others. I'll expand this article in the future with more detailed info on each type as I get it.
A300 - List of helpfull websites and tools
Before we get into the second half of this article there are a few websites and links that I think would really help you out as either research on your own or to use (like i do) as a nice little army of reference material if there is ever anything you come across that you haven't seen before or that you were wondering.
RadioLabs They have probably the best collection of information about wifi tools strategies and hardware around without crossing the line into "Tech-Talk Gibberish".
Windows Tools - Network Stumbler or Vistumbler. Try NetStumble first to see if its compatible with your system. If that doesn't work get the alternative. SUPER handy tools to monitor very detailed information about your network connection strength, speed, location, etc.
DXZone Tutorials HUGE Wifi Tutorials Database
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Section B: Build A Cheap Antenna
B100 - Think like MacGyver!
Step-By-Step Walkthrough of a build of a WiFi Antenna
When i started writing this tutorial I had the plan to make another Yagi similar to the one that I carry with me in my truck. After a couple days went by, however i notcied a few things lying around my garage that I thought were interesting so I've changed my plans a bit.
Instead of the yagi, I'm going to be taking bits and pieces of junk that I've picked up through the garage and closets over the past couple of days and turn them into a kickass portable WiFi Parabolic Antenna.....Hopefully. I'm writing this tutorial as I actually build it so by the time I get done you'll all know the results at the same time I do. We'll see how it goes.
NOTE & WARNING: please remember throughout this step by step lesson that the purpose of me doing this specific antenna build here is to show everyone how flexible some of these materials can be. Just because whatever you end up building isnt as complex and chic as a New Mexico Satellite Dish Array doesn't mean you have to "leave it to the pros". Take these lessons and do the work for yourself. Experiment with different materials and layouts. Figure out what works and what doesn't for yourself. Thats the best part of doing stuff like this.
B200 - Parts You'll Need
Okay, what I have decided to use for this project is as follows:
1. A broken older DSL Modem/Router that I got for free from someone who was just going to toss it since the power inputs are completely fried. There were 2 pieces on it that I spotted and couldn't let him toss without claiming them: both the male (from the unit itself) and female (from the screw end on the cheapo plastic antenna on the back) connectors that you'll need to transport the signal from whatever antenna you're using into your computer.
2. The suction cup antenna paddle that originally was on a wireless Print/Fax/Copy machine to recieve the wireless commands. I kept on to it because I knew that the circutBoard inside the Dipole Paddle was already wired up and specifically designed for receiving a wireless signal. It had salvage me written all over it.
3. A broken desk lamp with an adjustable neck. I LOVE these things and i've used them several times before on antenna jobs. They work great for smaller units that are meant to be portable. The adjustable neck is nearly perfect for holding the recieving hardware because you can make tuning adjustments to it just by bending it.
4. Some Aluminum tape or Tin Foil, or Signal Reflective Film (HOT TIP: I've picked up a dozen or so sheets of this signal reflective film over the past few months for free by picking up laptops that people are throwing away and taking apart the lid/screen mechanizm. Behind the Screen is that film. its glued on there but it doesn't take much effort to peel it right off all in one piece.
5. Some tools, a few screws, and a drill.
I know that most of you arent going to have this exact stuff laying around like I do most of the time. But since I got it all for free with hardly any effort its not that difficult to track this list down(or something close to it). Use your imagination. If you think you have something that could work or you have something relatively close....use it and see how the Network Stumbler tests it out.
B300 - Assembly
6. Okay, first thing is first. I need to pull out the pieces that I'm going to be using from these other junk items. For the male/female connectors I just need to remove the panel and unscrew the connector then unplug the feed from the card inside. for the female part since I'm not going to use the dipole antenna itself, all i need is the screw in part. A word of warning here, these little phuckers are a pain in the ass to pull apart without damaging the screw end. Once you get the elbow and the antenna off of it you should be left with this: Voila....just saved myself 5 bucks already. Take notice here of the preconnected wire coming off of the back of this connector. Gadgets like this aren't all like this but there are a few that have this premade attachment. Its a nice little suprise if you are one that doesn't have an external antenna plug on your wifi card.
7. Next comes the old paddle dipole antenna from the wireless printer. Nothin fancy here except trimming off some extra fat. The only things that I want are the antenna circutboard itself and the cord thats already connected to it. Trim off all of that plastic and set the wire still attached to the board aside for now.
P.S. Thats my pitt "Kilo" in that picture. He ended up gnawing on all the extra parts that I didn't use in the antenna until by the time I finished doing this there was a big pile of shredded plastic and bits of cord everywhere!.
8. Now i'll be cleaning the extra pieces off of the broken lamp. I removed the bulb housing, all the cables, and the baseplate, leaving just the top part of the stand, the neck, and the main bulb section.
9. Here comes the trickiest part. The female connector that came off of the little dipole antenna from the router, we're going to need to solder a couple of wires in there. This micro-soldering is a tricky job and it took me several screwups and frusterated attempts before I finally started doing these correctly consistantly without either melting out the center pin or getting a cold solder that broke off whenever I moved it the first time. Just a word of warning, take your time, practice on some scrap, and relax....cuz if you've never done it before, chances are you're gonna Eff that one up the first time.
Heres what you do: one wire needs to be soldered into that center part (that eeeeeeedie beeeeedie lil pin surrounded by plastic) and the second needs to be connected to the shell surrounding the plastic....
10. Next up, unscrew the lamp head fromthe neck and feed the cord thats attached to the printer wireless board that we took apart earlier all the way through it. When you rescrew the neck in it should just barely snug up to that wire because of the curve of the lamp dome.
11. Now in order for us to find out exactly where inside that dome we are going to be securing that reciever card we first have to do some calculating. using a calculator that I originally got from the website I mentioned earlier that has a list of different ones, I imput the Width and Depth of the Parabola at the center. NOTE: I'm not going to be leaving that little bottleneck of empty space that extends back past where the main dome is. I'll be covering that over in the next step when I shape the inside with my reflective tape WHICH MEANS in the measurements for DEPTH I have to make sure that i'm measuring from where the back of the concave WILL be since adding those few extra inches would throw the whole calculation off. Imputting these correct measurements into the calculator I come up with the "FOCAL POINT" This is the honeypot. Its where all of the reflected and directed signals are going to be going. This measurement is what we use to find out where and how we are going to secure the reciever (in this case, the Printer wifi board) You want the receiver to have its best signal grabbing capability at that spot. NOTE Always use 2450 Mhz in wifi calculations!
12. now you can use whatever reflective material you're using to shape the inside of the bulb dome until its shaped like one half of a ball. Then I cut an opening and made a little makeshift gasket out of a little bit of electrical tape so that the reflective metal wouldn't be touching my antenna reciever and fed the antenna through.
13. Okay the only thing left to do is secure the wire and attach the other plug. You are going to want to keep that wire as short as you can possibly stand it. the signal dies quick in the cable so once you figure how much you'll need to move around, cut off anything extra.
14. The last part is the other plug. If you already have an external antenna jack on your system, you're done except the tuning and testing. If you don't you'll need to plug it into a wifi card antenna jack or LOOK SOMEWHERE ELSE FOR INSTRUCTIONS ON HOW TO SOLDER ANTENNA WIRES INTO YOUR MOBO...'let me say this...I would strongly recommend you wait until you can find a better way to hook up an external antenna to your computer rather than go forward and try to jack into the ports on your internal wifi card. Messing around in those compartments could end up turning your computer into a paperweight if you have a twitch at the wrong time. Thats my little speech on that but i'm not your mother do what you please....Usually tho you can find a cheap PCI card or USB wifi card at a discount store if you don't already have another option.
B400 - Tuning & Testing
Once everything is plugged in and configured right you'll have to tune and tweak your antenna until you have it where you want it. The best way I've found to do this is to start off pointing in one direction level with the horizon and start Network Stumbler and wait for it to start recieving signals. Once the signals are steady I rotate one direction about 5 degrees and then stop and check to see if I'm getting MORE AP's, Stronger Signals from anything, losing connection signal, etc etc. Then I'll go another 5-10 degrees and check again. When I find a decent connection what i normally do is make a note of what general direction and elevation on the antenna gets that link so that I can reset it there later but continue checking for more configurations. Once I've gone about 90 degrees in one direction I'll add or subtract a few degrees elevation (point it up or down) and swing back the other way again.
The general rule I follow is to move VERY slowly, watch for strong signals and zero them in when I see them, and don't forget that an antenna has to be set angle, direction, and elevation (so every which way you can tilt or turn). Don't forget to go up and down.
Here is a screenshot of Vistumbler showing my connection strength as I turn it just BARELY and get a LOCK on the AP. A few notes about this connection:
*This AP is actually a mile away from my window
*I have a clear line of sight to the house where it is at
*When the antenna is disconnected, my laptop wifi card doesn't see that AP by itself
*WIth the Antenna tuned in I have nearly full connection speeds. (enough that I can stream HD Movies with no skipping or buffering)
END001- Conclusion
If anyone has any questions or comments please feel free to let me know. I really hope this may help some of you and I hope you enjoyed the article.
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