Nov 15, 2005 - Wireless enthusiasts have been repurposing satellite dishes for a couple. Marker and began bending the wire into a double diamond shape.
I Have Answers. You need a WiFi Router or WiFi Networking card for your pc or laptop, BUT, the important part its that it has a connector for a WiFi external antenna. This connector is where the cable from this antenna connects.
It will be an SMA style connector and intended for 50ohm coaxial cable. If you are trying to use cable tv cable you will need an F to SMA adapter. If you are using a WiFi router this is where your antenna cable goes and network cable connects to from your pc. If you are using a WiFi card in your pc, this is where your SMA connector will be, which is where your antenna is connected. I have another type of WiFi adapter that I use.
It connects to my pc by usb and offers up to 27db gain. I can easily connect to a WiFi network 1 mile away with just the antenna that comes in the package.
It was $38 dollars at Fry's Electronics. With this antenna hack antenna, I should be able to connect to a WiFi network at least 10mi away. Hello, i have a bit of a problem. Help me out on this. Isnt it that satellite frequency is different from wifi? That means the focal lenght of the feedhorn from the disc would vary depending on the application.
![Double biquad wifi dish network Double biquad wifi dish network](/uploads/1/2/5/3/125388358/390905442.jpg)
If i am getting 1800mhz which is standard of satellite broadcast, and my wifi is 2.4ghz, how is it that we used the same lenght by installing the quad to the feedhorn which is designed for satellite?shouldnt we have calculated the concentrating point of the disc to match 2.4ghz? Which i think should be nearer than the set arm for the satellite reciever? You can respond thru [email protected] too Reply. That was the simple version Aaron. Couldn't imagine how they could have made that simpler and still conveyed any amount of useful information.
Who is asking repetitive questions. Needs to start by reading up on the subject you wish to understand, how the hell you going to build a repeater or signal booster or amplification unit.
Or even a parabolic collection unit to focus signals and not have at least SOME level of understanding of what the signals are and how they are procreated through space, collected, transmitted, etc. That's like building a gun without understanding anything of explosives., either its useless, or, deadly. READ A BOOK, E BOOK, MANUAL STOP BEING STUPID HAHAHA - BTW I ain't knocking on you specifically Aaron, more so anyone you were aiming to 'help' with that statement, we should never dumb things down. Instead, they should smarten up. I will try and shed some light on the subject as it seems the author of the video may have abandoned the comment feed. As for the comment about the distance of the feedhorn being relative to the frequency alignment. In theory you are correct, it would be intensley important had he been transmitting in that frequency range, However I believe he built this for reception only therefore his wrong distance will only result in a lower db gain, however if my calculations are correct he was recieveing a 24 db gain, witch is a very good gain and can result in a much needed distance boost.
I would however like to see the gain we might obtain if we shorten the distance of the feedhorn relative to the dish itself, with that being said I shall address those of you who continue to ask were to hookup the other end of the coax on the computer. For those of you using a desktop with an internall pci wifi card, most if not all of these are equiped with an external antenna jack, you should be able to find the right type of coax end that will screw into place on your antenna connector on the back of your computer, most likely at rad shack. For those of you with laptop computers: If you use the internal wifi that comes with the laptop you are most likely out of luck, as only extremely high end laptops will include an external wifi jack with the built in wifi, However if you use a pcmia slot or usb wifi adapter there are some higher end wifi cards available that have an external antenna connector that uses the same connection end as those on the desktop computers therefore that is were you would connect the other end of the coax. I will be building one of these antenna's and experimenting with the feedhorn distance, I will be sure to let everyone know how it turns out. As for now I am receiving my wifi signal from about 3 miles away with a simple windfield type high gain antenna built using a 2 meter amateur antenna that is intended for the 14x.xxx mhz range, witch is no we Reply. The design is a good one that combines the parabolic reflector from the satellite dish with the biquad style of sardine can fame. The important thing to remember in all of these is to get the measurements right.
The 2.4GHz frequency bands require you to use fractions and multiples of the 125mm wavelength. This means 31.25mm (1/4 wavelength) pops up in the measurements often. Distance from dipole to dish also a multiple of 125mm for full wavelength. It could be argued that the height of the biquad dipole should be 1/4 wavelength above the brass sheet. In Melbourne Australia, we have a 65km link between Mt Dandenong and the Western suburbs based on a Galaxy antenna (similar to the sat dish here) rigged up to a pineapple juice can (Golden Circle). The dipole is drilled 31mm from the base of the can (drill into the A in 'FAT CONTENT' on the label) for the exact drill point.
24dBi gain on the antenna makes it a beautiful focus on the beam. Keep the cables thick, and straight and short as possible. The signal drops off very quickly in this frequency over bent cables, thin cables, connectors, even ridges on the inside of the can. Minimise all of these and use netstumbler to experiment on the best dimensions. Good luck and happy surfing.
Here's my question/issue with the design. The middle coax wire is soldered to the bent copper wire is soldered to the copper pipe, which in turn is soldered to the reflector. Making the reflector part of the antenna.
But the bigger issue is the grounding outside shield of the coax is then ALSO soldered to the copper tube, in affect shorting the signal carrying internal coax conductor to the exterior coax shield. This has to be hell on the wifi radio (SWR, etc) It would be much better in my mind to use a piece of PVC instead of the copper tubing, epoxy the bent wire to the PVC, epoxy the PVC to the reflector, and solder the coax's external shield to the reflector there by eliminating the grounding between the two coax lines (otherwise the ohm rating of the coax is nil.
Which would be bad for any amp's output stage) Reply. Hello sir, i want to get internet connection using a dish antenna.i saw posts in which some one said that he didnt paid for it. But i need to get the wifi signal provided by my college into my room near by using such an antenna. Or how can i get free internet.i dont know the thickness and dimensions of the materials which i need to use in making such an antenna.how can i even connect the coax cable to my laptop to connect to internet.do i need any extra software to run it.Can any one please provide me with detailed instructions to make one. I am quiet interested inn. I hate stupid and/or lazy people.
![Double Double](http://www.antennamagus.com/blog/resources/2009/12/BiQuad-Top-view.png)
Do a little research before asking stupid questions folks. And yes, this does work very well as long as you take your time, have all the measurements correct, and follow the directions. You will need to make SMALL adjustments to the dish to focus it in on the router you're trying to 'borrow' the wifi from since this has a narrow focus, and if there are objects in between your dish and the router such as trees, buildings, etc. You will have varying degrees of success.
KO4BB's 2.4GHz Antenna Help keep this site free: 2.4 GHz antenna for Lunar Orbiter The Japanese have a spacecraft orbiting the moon, the Japanese Lunar Orbiter SELENE. That by itself is interesting but it did not get much press coverage here in the US (somehow that is not surprising.) The more interesting part is that in spite of very modest power, it is possible to receive some of the spacecraft signals with simple equipment. The easiest signal to receive from the orbiter is a beacon at 2263.602 MHz +/- doppler, which can be as high as +/- 22 kHz.
A number of people in the Microwave Mailing List have reported hearing the beacon quite clearly with modest systems, so I wanted to try too. Any receiving station is composed of two major components:. An antenna. A receiver The Antenna The antenna is usually the most important part of any receiving station.
If you cannot capture the signal, there is little that electronics can do to bring it out, even though modern digital signal processing techniques are quite miraculous. While the signal appears quite strong (by comparison to other signals that might come from outside the earth's immediate vicinity), it has travelled 384,403 km (about 240,000 miles) so it would be best to make sure we don't loose a few dBs too many. I could have built a helix antenna with the right polarization, which would have been the perfect match for the signals sent by the probe, but I wanted to use a DBS dish I had in the garage. It was discarded by my neighbors after an upgrade.
So I built a simple feed to drive the dish. The dish is offset fed, 22' tall and 20.5 wide, it came from a dual LNB DISH Network system. The gain of the dish should more than offset the loss due to non-optimal polarization. There are a number of ways to illuminate a dish (the term used to describe the proper application of power across the entire surface of the dish.) A simple feed design for 2.4 GHz is the bi-quad. There are many descriptions on the Internet because they are used to extend the range of 802.11b/g Wifi networks.
If you Google or, you will find lots of links to examples of construction. I found a few that I liked and made my own using what I had on hand. Here is my version of the modified DBS dish/feed for 2.4 GHz The bi-quad radiator is supported by a short piece of.141 semi-rigid cable that was already attached to a bulkhead SMA connector, ideal to plug right into a DBM. I have a few right angle pieces of aluminum sheet 0.045' (a tad too wide, but nobody has complained.), two made a handy reflector.
A piece of heavy coat hanger wire ties the reflector to the dish and stiffens it. Some people might call it flimsy, I prefer to call it 'dynamically adjustable'. I located the feed (axially) by eyeballing the approximate target point of the original feed on the dish. I then made a pencil mark on the dish and measured the distance between that point and the apperture of the original feed. When I installed my feed, I bent the supports until the bi-quad was approximately in the same location (within about 1/2 inch). The picture below shows the new feed installed on the antenna, and behind is the old Ku band feed for comparison. I made a stand with PVC pipe and a cement block (see pictures).
That will work for a temporary operation. The stand is long enough to allow the antenna to peek at the moon through a window which is facing south and upstairs, so it's just right to see the moon, and it's close to the ham shack (of course:-) The PVC tube is held in place with a wood block appropriately cut and two wood shims. The Receiver The receiver is composed of an LNA (not really as low noise as it should be), driving a Double Balanced Mixer, the output of the DBM drives a ham transceiver FT-817 used simply as a receiver (microphone unplugged to avoid accidents) The mixer's LO port is driven from a microwave signal generator HP 8672A. This is not the way you would want to go about building a satellite receiver, but it was available and I was in a hurry. The FT-817 can be used either to listen to signals directly through the speaker, or can drive the audio input of a laptop running Spectran for display. This receiver could be considerably improved by using a real low noise amplifier and an image filter.
A noise figure of less than 0.6 dB can be achieved in this band with P-HEMT transistors, check HP AN1129 application note. As long as an LNA is used in front of the mixer, an image filter should be installed between the LNA and the mixer. This will provide 3dB improvement of the signal-to-noise ratio, regardless of the noise figure of the LNA. I am planning to build a pipe cap filter for that.
I have written a page about checking the Noise Figure of the LNA. General setup information When selecting a LO frequency, make sure to avoid getting the 802.11 stuff at 2.4 GHz in the image. I use low side injection and a low IF (28-30MHz or less) so that I can run a fairly long coax cable (25') from the IF output of the mixer back to the shack where the IF radio and the rest of the equipment is, without having too much loss. Normally, a low IF should be avoided because it makes the image reject filter harder to design and build. However, as you can see from the plot above, an inexpensive pipe cap filter will easily provide about 19 dB of attenuation at 30 MHz and 30 dB at 100 MHz below the receive frequency, so IF frequencies as low as 30 MHz would be usable. With a 30 MHz IF, the image frequency would be at 60 MHz from the receive frequency, where the filter has about 25 dB of attenuation.
Michael Fletcher, in Finland, has reported receiving SELENE with as little as a paper click (extended!) as an antenna. Here is a picture of Selene's signal taken by Joe Ruggieri KI4NPV on December 26, 2007: Comments welcome.
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