Yea I know, you don't believe me. 1/4 mile? Shenanigans.

Still reading? Great.
The whole thing started when I dropped my friend off for Horse lessons and didn't want to drive all the way home only to drive back to pick her up in an hour and a half. So what did I do? Drove to the closest neighborhood and got on an open WIFI network.

[NOTE: Connecting to someone’s WIFI without their permission is illegal in some areas!!!]
The network I connected to was a local realtor’s OPEN HOUSE FREE PUBLIC WIFI network…so I didn’t break any laws.

The problem was, the signal was very weak and I had to hold the computer at odd angles just to do a simple google search.

So after about twenty minutes of searching and finding things like “wokfi” and “parabolic asian cookware” I had the basic idea of what I needed to do; Concentrate the signal onto the antenna using a parabola. After a bit more searching I found out how to build a parabola out of a cd and a glass pot top, but I figured that it would be too weak for the distances that I am looking for [I would like to be able to connect right from the parking lot at the stables] Then there was the world record holder who had built a reflector out of a 10 foot diameter dish but that was WAY too big. So I compromised and picked up a rooftop satellite dish from a guy on Craigslist.org.

Long story short I built the thing and drove out to the stables, turned the rig on, started netstumbler, and started looking it took a little bit but I got the right angle to lock onto a signal and SHAZAM! I was connected!

So I knew that I had working signal, not just a fizzled connection from the router. The noise was at -100 and the signal was hovering around -75 or so. Not the fastest connection but based on the fact that I was ¼ of a mile away from the router I would say I was doing pretty darn good!

Ok enough with the stories, how do you build the darn thing!

You need:
A satellite dish [and the four screws holding it to the roof [YMMV]
A pair of scrap 2x4’s
A tin can [green bean sized]
A usb extention cord 
A usb wireless adapter [in this build I am using the cheapest adapter I could find [$30 at target]
Two wood screws long enough to screw your two 2x4’s together
Some hot glue
An unwanted cd [I picked up a free netzero disk at Wally’s]
A glass pot lid shaped like a parabola
Some spray paint to make it look pretty
And some carpet of you are going to be mounting it to the roof of your car so It won’t scratch it.

The total cost for the build was only the $30 for the usb adapter, I had everything else on hand.

If you bought everything new it would cost around $60 [Not counting the dish]

Step 1: Form The Rear Reflector

Step 1:

Take your parabolic lid, remove the handle, it should just be a screw.
Take your CD, place it mirror side up in the glass lid.
Place the CD in the oven THEN set the oven to 300 degrees [faren if anybody is wondering]
[WARNING: If you put the cd in a preheated oven the cd will crack and the foil will wrinkle! This is bad for signal reflection! Start with a cold oven.]

Leave the CD in there for about an hour to an hour and a half [I just put it in there while I was building the rest of the rig]

After it is done forming take it out of the oven and IMMEDIATELY depress the center of the disk with something heat resistant like a spoon to form the CD to the parabola.

Let cool.

One question what is that cable you insert at the end of the dish
<p>USB extension cable</p>
<p>My music studio only has windows into a small square court yard in the cennter of a building with corridors and outer offices....many walls. And even attaching it outside in the courtyard might raise questions from others in the building.</p>
<p>WIFI using a dish can surpass what most people think are capable. If you were to use a circular polarized antenna at the feed point, and aim it at a second dish retrofitted in the same manner, you could get line of sight without a minimum of interference from other signals as well as reduce rain fade. Over water, a good 30 miles could be realized... Nice instructable BTW :)</p>
Hey great article, i am gonna try this once it warms up outside. One question, instead of going into a laptop or pc is there some way I can connect to a router so I can make my own network?
<p>Great stuff. Love the DIY and the reuse of the sat dish. Got a question though, isn't there a simple 8 db type of directional antenna one could purchase and simply mount. Noticed some of the RV forums run into this issue and have found some solutions Will be talking to Wilson Electronics ( known for cellphone boosting ) , and Dlink about antenna.</p><p>The solution I am thinking off is an antenna mounted at roof line - 50 ohm cable in to house - 50 ohm adaptor to USB converter - wireless adaptor.</p><p>Also noticed some mention of Ubiquity modems , these usually work in pairs and are not addressing the issue you have provided.</p><p>Will paste what I find unless others post products they found off the shelf.</p>
<p>keep in mind that the IEEE 802.11b maximum LEGAL limit for a 21 dbi gain antenna is 20 mW. so make sure your power is not interfering with aircraft. that may be bad.</p>
<p>my sister is moving to the other side of the property. Is line of site going to be a problem??? It's less than a 1/4 mile. More like 100 yards...but a lot of trees? I think you have came up with a great project but not sure if it will work for us or not...</p>
<p>The USB adapter are a 3g modem ? What you used ?</p>
Fleetwood Mac didn't like the oven to much. Put it in a cold oven then set to 300°F. Only was in there for 15 minutes before I checked it. Cool effect though. Reacted to the heat almost like lexan!
Great project! Gonna build one this weekend. Do you know wether the distance of the &quot;feedhorn&quot; / CD reflector in relation to the main dish makes any difference? If the USB wifi adapter/CD is closer to the dish, would you get a better signal? I'm trying to build something like this to use on an island we own. Mainland is aprox 3/4 mile away. Wide open between island and wifi spot on land, just water... Thanks for your instructable!
I like your CD parabolic and how you mounted it on the arm. <br>However, a satellite dish like this is a offset antenna. If the dish would be mounted at 90 degree (vertical) ....straight up and down, then it would receive a signal from about 26 degrees up the skies. To receive a signal from a horizontal source then the dish has to point about 26 degrees toward ground.
That is about how it worked :) the adjustment bolts were loose enough to move the dish around and find the sweet spot using a program called ssid to measure signal over noise.
One more question. <br>Did you ever try to use a cd reflector shaped like a cone ? <br>It may trap more signals inside the cone and unto the wifi.
You aren't trying to trap the signal, you are trying to concentrate them on the antennae of your card, hence the parabolic shape.
Thank you for your response. <br>Where did you find the program ssid and how much money was it. <br>In the near future I like to build something like you did. <br> <br>
Google, it was free.
That is about how it worked :) the adjustment bolts were loose enough to move the dish around and find the sweet spot using a program called ssid to measure signal over noise.
So in your experiment the router is sending the signal a 1/4 mile to you, but your laptop could not see it without the dish?
It was more like 1/3 of a mile. But yes.
The wireless router is sending the signal a mile away?
Probably more, its just waves
you would be supprised how far that signal goes, i have picked up connection with a 9 foot dish over a mile away. <br>
How does this work if the router is not able to send wireless signal that far back to you?
WiFi Signal Amplifier Booster Manufacturers <br>http://www.powermicrowave.com/ <br>http://www.powermicrowave.com/en/4w-en.html <br>http://www.powermicrowave.com/2wen/2w-en.html
I just followed your formula with a slight variation with OUTSTANDING results. I live in a house in the country and there was no internet. I followed your instructions for building the rig..EXCEPT I took my Verizon USB (760) WAN data card and substituted that for WiFI. <br><br>When I started I had ZERO bars.. nothing.. after I build this rig.. I got FOUR BARS.. plugged it into my Cradlepoint mobile broadband router and now I have internet in my whole house. Once I get a broadband connection I will use this as a backup but you guys are lifesavers.. brilliant use of physics to solve problems.<br><br>
AWESOME! I'm glad I could help!
I am very excited to try this when I get all the materials. This will be a godlike tool to wifi dead zones in my house. Can't wait to build. <br> <br>Do you think you could connect the end of the antenna to a wireless bridge instead of a USB port? I think it would work, but I would like to know what you think.
Yes, I have also used it to concentrate tv and radio signals, if you were to polish the dish you can also use it to heat up cans of soup [physics is fun!]
Greetings,<br><br>I am not clear about the angles of the CD. Where is the focal point of the CD supposed to be? On the USB stick or on the satellite dish?<br><br>Would this work without the CD? What is the reason for two dishes?<br><br>How do I know if a pot lid is a parabola?<br><br>Thanks
if its curved lid, its a parabola, 99% of lids are. <br><br>The focal point of the satellite dish is supposed to be on the CD, it will usually be several inches across. The focal point of the CD is where you want your antenna. <br><br>This way you get two passes to catch the packets. The second parabola concentrates the signal to the size of a dime as opposed to a CD sized signal pattern.<br><br>You can find the focal point of your cd by aiming it at the light and moving your hand away from it until the light is as small as it can get [every parabola will be different]
THANK YOU FOR COMMENTING!!! YOU ARE MY FIRST COMMENT EVER!!!!<br><br>Where is the focal point of the CD supposed to be? On the USB stick or on the satellite dish? <br><br>[[[The focal point of the CD is supposed to be on the antenna of the USB adapter, in most cases it will be on the tip. You can find the focal point by aiming the dish at a light source and putting your hand in the reflection until you see the most concentrated spot. Then put your antenna there. On another note you do not have to use just a USB adapter for this build, if you have an external antenna for your WIFI device you can just put it through the hole instead. ]]]<br><br><br>Would this work without the CD?<br><br>[[[Long answer short: Yes... The rest of the answer: The rig will work with just the tin can cut in half as your reflector [that's what the can was in the first place, just mount the USB adapter in the center of the can.] With just the can configuration I picked up a signal at 1/4 mile but it was fizzy and always dropping out, however it would work at shorter distances just fine.<br>If you are afraid that oven forming the CD is complicated it really isn't, I will explain more below.]]]<br><br><br>What is the reason for two dishes?<br><br>[[[The second dish concentrates the signal better onto the antenna, the satellite dish makes a two and a half inch spot, meaning for every packet that the adapter catches, three more pass the antenna, and you get a weaker signal. The CD brings the spot down to 1/2 inch, which is a tiny bit bigger than the surface area of the antenna so around 90% of the packets are caught.]]] <br><br><br>How do I know if a pot lid is a parabola?<br><br>[[[There are three basic kinds of pan lids; flat, conical and parabolic. If it looks like a very wide dome, it's probably parabolic. Flat is...well flat. Conical looks like a very wide funnel with straight sides. Another identifier is the material it is made of, I have never seen a glass lid that wasn't a parabola...so a glass lid is your best bet]]] <br><br>Melting the CD:<br>[[[ It really is not as scary as it sounds to put a CD in the oven at 300* faren, <br>start with a cold oven, place the lid upside down [making a very wide bowl] and eyeball it to make it level. Now place your CD inside the lid and make sure it is level. Now close the door and turn the oven to 300* faren and go watch a movie. CD plastic can not combust at anywhere close to these temperatures so don't worry. It will smell a little [like burning plastic] but that just means that the molecules are loosening up and the CD is starting to sink and form the parabola. Due to the clear plastic ring in the center the CD will not completely form until you press on the center with a spoon. When the CD forms just take it out, press the center down, and let cool. THATS IT! <br><br>When your oven is cooling, crack the door open to allow any plastic molecules that have vaporised to escape, they won't stick to the sides of the oven but they will settle in the bottom if you do not vent them and you will melt them or burn them the next time you cook something at a high temperature. Just crack the door and you are fine]]]

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