Instructables

The Wireless Internet Cantenna gets Dished

Picture of The Wireless Internet Cantenna gets Dished
I just built this Cantenna, and I must have an addiction to the internet or something because I'm hot-rodding the poor thing.

In this, I describe how I use the Cantenna and add it to an old satellite dish.

First, you must have a Cantenna. If necessary, search for that on this site or in google.

Then, you need an old satellite dish. It might not be like the one I use here, so take a look at: http://people.wallawalla.edu/~Rob.Frohne/Airport/Primestar/Primestar.html This primestar has an easy to use feed arm. I had to improvise a method of mounting the can, because the arm on my dish doesn't go all the way to the feed-point area.

Tools were just a couple wrenches to re-configure the dish, a phillips screwdriver to rip apart the old lnb's, a utility knife and a roll of electrical tape. Oh, and an ink pen.
 
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Step 1: What the cat drug in

Picture of What the cat drug in
So I decide to build this, I drop by a friends place and grab his old dish and drive up to the shooting range. Now to see just what exactly I'm going to be dealing with.

There's a pair of LNB's on a y-adapter. The y-adapter is a two-piece clamshell plastic affair that looks rather doubtful. It looks like I'm going to have to add something to get from the arm to where the cantenna is going to go. Oh well, I'm feeling determined at this point. Besides, if I tear it apart enough, maybe something will inspire me. It's happened before
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wlambeth1 year ago
i have a question, if anybody can answer it please use the proper knowledge-base for the topic: i'm in the process of helping create a reliable network connection other than satellite or cell towers, i've found out how to create a satellite wifi setup, i run into a couple of issues, one is it is usb and is limited to 16 ft, i need to broadcast the signal several miles with line-of-sight, and theres lots of trees in the area, of up to 50+ ft tall and a good distance away from the house, i figured if a natual issue happens i could use a usb male to female adapter that connects into a 2.0 usb to ethernet adapter, which connects into a 100 ft cat5 cable, then i run into 2 issues one is that the tree maybe not 100% stable because of the bugs here which eat up pines & my second concern is the connection between the usb wifi adapter thats placed in the cantenna thats attached to the dish to broadcast several dbs (100s of miles might be needed for good source of network), i may need 20-60 dbs for this to work properly, but.. will the connection have issues if im using a adapter through to cat5 and back to usb to pc, can ethernet port be used instead of using 2 adapters on each end, meaning can i convert the usb to ethernet, then plug into the pc or do i need 2 adapters. question 2; if i choose to not post it uptop the tree, and use pbs piping to go straight up from a nearby location and secure it for making adjustments by cementing the base into the ground then putting the wifi dish uptop for fine tunning and secure it, would it work good or...what not, im posting this same message in several places to find help, if you can assist please message me on facebook "facebook.com/nekoneopaul" or by email "neopaul@gmail.com" , thanks.
Shadetree Engineer (author)  wlambeth1 year ago
You should look at Ubiquiti wifi radios on ebay. For example, you could get a 23 Db Airgrid like this: http://www.ubnt.com/airgrid - Ubiquiti radios like the Airgrid & Rocket M2 all run off of ethernet plus are powered over the same ethernet cable using a power injector which can be home-brewed easily. You can buy bulk cable, connectors & a crimper to make long cable runs up to 1000 feet from your router to where the radio & antenna is placed. The radios run on anything from 12 ~ 24 volts DC. The radios can be switched from the default 'adapter' mode to an access point mode by one click on a web based menu. The radios have a web-based configuration page built-in so you can use a laptop on it's own wifi link to aim the antenna or even just go with the built-in signal strength LED's on the side of the radio. Keep in mind to always look at the actual frequencies covered by the device if you want to try 802.11N because that standard is used in 2.4 Ghz only radios, where you might make the mistake of adding a 5 Ghz link at the other end!
Skeletel5 years ago
Can you make this thing wireless so that it Transmits to your house so that you can surf the web in your bedroom? And how many miles will it detect the WiFi signals for?
Shadetree Engineer (author)  Skeletel2 years ago
Just re-reading these comments, surprised I didn't think to make another pitch for running the free-to-download DD-WRT on a hacked router. This replacement router firmware has among other options, the ability to act as a repeater. The implication being that yes, you can make your wifi dish project into a wireless antenna. One antenna on the router can be selected for the feed to the dish, with the other antenna used to link wirelessly to your house. The router can be mounted so that you can stuff the existing antenna selected for the dish, right into a waveguide can - so no pigtail or soldering coax needed. You could even use a solar panel and rechargeable batteries to make the dish antenna completely wireless. What I'd like to see is for someone to include an IP GUI to run a pan/tilt mechanism on their dish antenna!
I have one of these set up inside my house and recieve signal from a site 6 miles away. it appears to have a -30dbm gain. Not too shabby for some scrap parts! I have seen articles where folks were using 2 home cordless telephones and linking them via two surplus 10' C-band dishes and they had a range LOS (Line of Sight) of 125 miles. You can also make one heck od a "Big Ear" listening device by placing a mic in the focal point. Even though the dish is mesh you'll get respectable amplification, but a replacing the mesh making it solid or placing foil or saran wrap, I know it sounds screwy or clear shipping tape, or my personal favorite, "The Handyman's Secret Weapon...DUCT TAPE!" on the mesh this will give a solid surface to reflect from as far as sound is concerned. It can also be used as a GIANT speaker where you could place one of those Pest eliminators in the focal point and move some rodents and any thing else that has sensitivity to high frequency sound. I watch way too much Red Green.
Hi Foxtrot70, Could you tell me where did you read that article where folks use 2 home cordless phone and 2 10` c-band dish to make a link of around 125 miles from each other,do they use any can with the adaptor, any yagi antenna can you explain a little or or can you give please give us the link...I m pretty interested thanks for your patient
Hi Marigo

Try this link, It was the DEFCON WiFi Shootout

http://www.unwiredadventures.com/unwire/2005/12/defcon_wifi_sho.html
Shadetree Engineer (author)  Foxtrot705 years ago
Like LRAD? Just don't get caught in public with that thing! And if for some reason the Active Denial System inspires you to place an array of 2000 watt magnetrons in front of your 10 foot dish....
Hmmm...I do have a spare Amana Microwave oven this has possibilities!
Shadetree Engineer (author)  Skeletel5 years ago
I'm sure the antenna could be rigged so that it not only connects wirelessly to a wi-fi enabled internet access point as described here in this instructable, but to also connect to your bedroom computer without a wired connection. The easiest way would probably be to use a second computer with two wi-fi adapters. One adapter rigged to connect to the net, the other to connect to your bedroom computer. Of course, you will need a third wi-fi adapter to be installed on your bedroom computer, and you need to enable a network bridge on the outdoor computer. I never used a bridge, so I can't say how to do that - except try google for net bridge building. It looked easy, anyways. Personally, I would recommend not spending all that extra cash on defeating the low budget nature of this instructable, and just get a powered usb cable to connect the bedroom computer to an outdoor antenna, based on this or better instructable. Usable range in miles: estimated - 0.1 miles Detecting a signal without hope of establishing any kind of connection: estimated - 5 miles
Oh well.(Shrug)Thanks anyway!
If you build up the dish antenna it will get a gain of about 30db, then go to this site www.primecellular.com and purchase the inside dome antenna P/N: CM222 on sale cost $38.95 this should work for you. It works on 2 bands 806-900mhz and 1700-2500mhz with a gain of 3db. Do not place the dome antenna in front of the dish antenna the signal will produce feed back ringing, if an amplifier is in the line this will cause damage to the amp. If the signal is still weak you will need to purchase an in line amplifier. Again go to Primecellular and look for wireless amplifiers for buildings. WARNING!!! Try the dish inside first. Keep in mind when you mount your dish antenna on the outside of your house or apt. you will need to earth ground the antenna mast and the antenna coax line failure to do this WILL result in lightening damage of the amplifier and also your house! Hope this helps.
I have just taken the LNB's out of a Dish Network 500 dish and used the gray shroud as a form and placed a bowtie antenna within with 2 ranges 2.4 Ghz and 1.9 Ghz. Again this unit is in my home office about 8' off the ground and shooting thru a 6" frame wall and the signal increases from -124dbm to -89dbm, now if I were to mount this on my roof it would have direct line of sight, should improve a little...LOL A LOT!
Now maybe I like to make things that have been over-killed but I was thinking if I used a 10 foot dish with a 4 foot yagi attached to the cantenna and then just as an added bonus to add a 180 db gain amp.

Could I get signal from over the horizon?

Now mind you I was just thinking, which gets me into trouble a lot of the time with my wife. But could this work?
This is a picture of what I am talking about. I think that it looks like a cross between a 50 cal. machine gun and a Star wars laser canon
Parabolic Yagi.jpg
Whoa! Careful you don't melt holes in the poor dish!

Seriously though, this isn't a good idea for a bunch of reasons, but I can appreciate the impulse.

The yagi extensions if designed right, will work best when used with a hot element mixed into their stack, near the rear, and not when fed from a wave-guide. So that will just result in a lot of signal getting blocked from the mass of metal in the way of the waveguide opening.

Then, a 4 foot yagi will lose power because after about the 12th element you will only be adding a small bit more. Then at around 25 elements, the signal will be getting absorbed by the metallic mass of any additional element. After 6 inches, all elements will be around 5/8ths inch spacing.

Then, you do not want to use a tightly designed yagi to illuminate a dish as the radiated pattern won't spread wide enough to cover the dish. By the way, you don't want to illuminate the very outer edge of any size dish. That loses some signal due to edge effects.

Then, using multiple radiating sources to illuminate the dish will likely have the signal cancelling itself out from interference patterns. Unless you have access to some very expensive technology to model the energy flow of the signal. Better off to leave the Star Wars stuff to the government.

Now, that being said, a 10 foot dish with a well-matched & designed radiating source will get you to the horizon. Over will require a repeater station, as these frequencies like to travel in straight lines.
I don't understand what you mean by a "Hot Element"

I also am not sure if my picture explained it or not but I was thinking that the dish would have a broader area to receive a signal and then reflect the signal at its focal point to the yagi in hopes that it could be a bit less of pin point aiming in the direction of a tower.

Now I was only thinking that if any one of the components were able to boost the signal strength then maybe it would do a lot better if I used all of them into one unit.

On another note would it work if I used the cantenna at the back of the dish with a shorter yagi extending outward?

I am good at building stuff like computers and designing boats and I put together some really weird things that do seem to work.
But I don't understand the math that is involved with wave forms, in fact I am pretty poor when it comes to math.
So please bare with me if I seem a bit mentally challenged But I do work at trying to figure this all out.

Thank you very much for your feed back.
You can ignore the math, if you can accept a 'luck of the draw' in your design. That's why you should stick with pre-built components that have had the tricky parts designed right.

What I mean by a 'hot element' is the little bit of wire that is connected directly to the end of the antenna wire. This usually is simply a stripped length of the coax, with the bare end being the correct wavelength.

You have the right idea for a larger dish being able to capture more signal, but that yagi idea will likely lose a lot of that gain. So you might wind-up with a noticeable improvement overall, but not by as much as you could have had. But only if the yagi can radiate the majority of it's signal in a cone pattern that covers 90% of the dish. A very long, multi-element yagi will focus all of it's signal right at the center of the dish - right where the cantenna is shadowing the dish the most. You can aim the cantenna off to one side, like the Dish Networks antennas are designed, so that the dish is reflecting the signal away from the cantenna. But you will still have the problem of only using a small area of the dish, if you use a multi-element yagi.

Any dish you find is a reflector, so putting the cantenna at the back will require a second reflector at the front, where the cantenna would have been. In this scenario, a multi-element yagi might work ok, as the second reflector should be designed to accept a narrow beam, then reflect that onto the wider main dish. But putting a multi-element yagi in front of a waveguide such as the cantenna is another problem. You would be better off just building a wifi yagi, and forget about the waveguide can. There are many good examples of military radars that use a two-reflector set-up. But the second reflector is not normally seen as a signal boosting device, as it will introduce another set of losses. Putting any kind of metallic plane, to the rear of a yagi, will enhance it's ground-plane effect. Which will improve the quality of the signal, but not because the dish is focusing more signal.

If you do not want to learn the engineering, then you really ought to stick with proven designs. That would just be the most practical choice to get any kind of antenna up & running, to the best of your abilities.

Take a look at http://www.engadget.com/2007/06/19/venezuelans-set-new-wifi-distance-record-237-miles/
hhamer3 years ago
What is the range of that:?
Shadetree Engineer (author)  hhamer3 years ago
On step , there's a box in the pic, you let your mouse go to work on that, it tells you...
dflores33 years ago
What about using a more old antenna, the first ones, does improve the range? (you know the big first ones)
Shadetree Engineer (author)  dflores33 years ago
By all means, yes! You can use the reflector from any sat dish, and the bigger it is, the more signal you can catch. If it still has it's feed still mounted, then measure that very carefully to see where the engineers put the focal-point, as that where you want your Wi-Fi feed to be positioned.

All of the world records for Wi-Fi connections over the greatest range all used the biggest dishes available. The small percentage of signal lost from a center-feed shadowing the signal is more than made-up for by the extra diameter.

I'm very strongly in favor of using an ethernet based Wi-Fi for the adapter. You should take a look at this: http://www.dd-wrt.com/site/index - and consider that their firmware has the option to change a router into an adapter that can be plugged into another router. The main advantage here is that an ethernet cable can go well over 100 feet. And if you add-in a 'power-over ethernet', you have a one-cable solution to go from any room in your house to the original location of the sat dish, or to any suitable high-ground such as your roof. No awkward hanging a lap-top out a window kind of thing. It doesn't take much to adapt an antenna on a router to a directional feed. You might not want to use both antennas though. I think the alternate firmware supports turning one antenna off.

Let me know what you come up with.
This is my work in progress . still need to make the biquad antenna tip . and the umbrella text is shoped but the logo is painted and finished
0729092215.jpg
Looks good, the text part doesn't quite come through though. I've been thinking about fractal antennas, like the evolutionary next step from the bi-quad.
thanks ...the text is gunna say Umbrella corp. ...from resident evil .but i cant figure how to stencil it the right way ...and a fractal sounds cool but i wouldnt have a clue how to tune it to 2.4gh. good idea though
cut the stencil in cardstock, spray it onto contact paper and cut it again. stick to dish spray and peel. for 2 colors you need 2 stencils, registration marks help as well.
The red & white graphic could be hand-drawn, the text can be ink-jet printed onto 8.5x11 clear plastic used for over-head projectors then cut and glued with something to waterproof the edges. The design of a fractal version of 802.11 is very cutting edge. It's basically taking a normal length of wire cut for a specific frequency and bending it according to fractal geometry so that the wire occupies less space. This will allow a more compact feed to your dish. If your bi-quad uses a back-plane, then you can consider that the size of the back-plane can be reduced by half or more. You could try image.google searching for 'fractal-antenna' then take a likely pattern, print that at different scales untill you are able to take a wire of say 4.845 inches in length (center full wave of 802.11 channel 6) and are able to bend the wire to follow the printed pattern. Re-scale the print untill the wire fits it's length perfectly to the pattern. Then maybe just bend a set of wires to adapt to your bi-quad. how to fit those for impedance matching I'll leave to your own imagination...
Saturn V3 years ago
I looked at this just because of the title. Love it!!!!!
Shadetree Engineer (author)  Saturn V3 years ago
Thanks!
lane294 years ago
i just switched to dish aand they left me with a older one great idea
Shadetree Engineer (author)  lane294 years ago
I've had a few ideas since then. Did you know that you can use a wireless router as an adapter to connect to another wireless router? Check this site: http://www.dd-wrt.com/site/index They make it easy to do this, once you get their firmware loaded.... Then something I've tried with good results, to add to that router - take one of those flat square antennas from a 2.4 Ghz wireless video camera and solder it in place of the routers antenna. That would give you a really nice center-piece for a parabolic dish. It's a directional patch antenna that would cover an area about the same size as a small dish. Using a router means you can run an ethernet cable that's a lot longer than any usb cable, and you don't need any kind of drivers installed on your computer to make the antenna work. There's also another option called power-over-ethernet, that would make the router a one-wire installation to wherever you can run a 300 foot ethernet cable.
Gathrax4 years ago
Wow, i just found this site and posted a similar project, though mine is crude and built with no knowledge of how it works, just knowing it does. I guess i should have checked to make sure there were no similar posts already. Good job on this though, im going to do some research and rethink my design.
sal8764 years ago

http://urbanwireless.info has a few good tutorials on making these type's of antennas
H3xx4 years ago
I really like your idea to reformat the structure of your dish. Naturally, satellite dishes are designed to project all of the devices waves straight up to the satellite in space. turning the dish upside down, in my opinion, is brilliant! Not only does your dish point in the right direction, but it also makes it more compact and usable! Bravo!
Shadetree Engineer (author)  H3xx4 years ago
Thanks. There were a few minutes spent with all the pieces laying loose, where I just kept moving parts around until it looked like this. This configuration balances perfectly on that 4 by 8 inch foot. In this picture, the dish is aimed down about 20 degrees. One slight flaw in this configuration is that the can will pick up more background noise than if it were at the bottom of the dish aimed upwards into the reflector. But as I've noticed that the can by itself will pick up signals from 90 degrees to the sides, it wouldn't really make any difference here.
Well if were designed to be perfect, it would probably be too good to be true. I'm going to use my dish to increase my cell signal. I get my internet through tethering with my phone, because I live in a pretty rural area. Not a lot of wifi connections around, and the few that are, are secured. So I'm going to try and find which direction gives the best signal and mount it in that direction. Wish me luck on that goose chase! ;)
Shadetree Engineer (author)  H3xx4 years ago
Should work, if you start with the WokFi approach and just place your phone in the focal point of the dish. The bigger the dish, the better it will work.

The money approach would be to spend $400 on a cell-phone amplifier kit, available from http://www.wilsonelectronics.com

I've been thinking about combining one of those with an unlimited cell phone plan like with http://www.zer01mobile.com/
cx420ns5 years ago
ahhh you rule, i'm too poor for the net right now, had to get it cut off last month. i can pick up one bar on a router somewhere nearby but it's not enough to connect. i will have to do this very soon.
Shadetree Engineer (author)  cx420ns5 years ago
Seeing as I wouldn't even get one bar if I took the wifi adapter off of this antenna, then yes, you should do something like this soon!
Gamer9175 years ago
Finally i can get free internet connection anywhere in a city (So many cafes w/ free wifi)
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