Another downside is that birds like to perch on them. If you want to test the parabolic theory, hold a large bowl in front of your face and speak into it. The coverage width and elevation is comparable to that of a Yagi antenna. They can help you reach Wi-Fi hotspots that might otherwise be out of reach. There are a lot of DIY enthusiasts these days. Some are downright ugly.
Others are quite impressive. Regardless of the type of antenna that you use, there is one thing that absolutely must be correct and that is the polarity. The broadcasting and receiving antenna must use the same polarity. Good performance is all about a strong signal. Polarization is determined by the physical position of the antenna.
Polarization is extremely important. A Yagi antenna with vertical elements is also vertical polarized. But if you turn the antenna so that the elements are sideways, the antenna is then polarized horizontally.
Unlike the actual radio transmitter itself, antenna power is not measured in output power. For the transmitting antenna, gain is the measurement of how well the antenna converts the transmit power into a radio wave that can be sent. Just remember, the general idea is to reduce the amount of loss and retain as much gain as possible. Antenna Gain and Cable Loss are values that are constant no matter what power level you are referring to. The referenced unit is exactly one milliwatt.
Since it uses a reference point of exactly one milliwatt, it is an absolute unit of measure. The conversion of watts to dBm uses a complex formula that goes beyond the scope of this section. In short, 1 watt or mW is equal to 30dBm. If you have cable loss of 2 dBi based on your cable length and diameter , but a gain of 7.
With outdoor applications and runs over 4 feet long, use low-loss cable such as: LMR Can you remember, almost all internal card come with 'BlueTooth' capability? And as both of connector share same 'Ground Plate' scenario become more complicated as you might introducing total new kind of environment where both antenna fighting each other or even your attached antenna is not for WiFi range at all!
Try changing few other available antena around before go for final dicission Good Luck. I would love to do this mod with usb booster to my inspiration as it can not connectv to o my network 20m's away! HI interested indeed of your usb wifi amp so it doesnt come already usb? Reply 13 years ago on Step 5. Hey guys Well I havent got around to do usb amp isble.
So I just tell ya how in words. Its realy simple. The amp came with a wall wart power adaptor, but thats not to travel friendly. Usb plugs have 5. I used a 1watt amp. Then you need a usb plug, I just choped 12" off an old usb mouse. So in the usb plug red is positive and black is obviously negative. They are the 2 outer most pins. The 2 inner data ones we wont be using. Now open up the amp with the 2 screws, and very carefully remove the power plug jack. I used a dremel.
If I remember correctly the far left is positive and the middle is negative. I just touched the wires to it for a second till the amp light came on to find the right pin.
Now feed the usb cable through the hole where the power jack used to be and tie a knot so it wont get pulled out. Now solder the Red and Black Usb wires to the solder pads on the amp. Close her back up and shes ready to go : I used it at BWI airport the other day and picked up like four pages of routers Reply 9 years ago on Introduction. Reply 11 years ago on Introduction. That is a great modification that you have done. It was the inspiration for performing a similar mod to a dell inspiron The antenna mod works great.
I ordered a 1 watt broadband amp to use with the laptop and it also works great but I'm wondering about the specs on the amp that you used as the wall adapter is 6vdc ma, this power requirement far exceeds usb power.
If you want to provde strong wireless internet coverage to an area, but cannot provide a fiber optic or ethernet cable to your wireless router, again consider using a wireless bridge to substitute for the unavailable cable, and connect the bridge to the router. A wireless bridge is a better solution for situations such as:. If you are interested in building a high gain wifi yagi antenna, continue reading below for the details.
The yagi wifi antenna design depicted here can be built in just an hour or two, and it works great! It is computer designed, made of wood and wire, and provides high gain and directivity. It is directional - favoring wi-fi signals in one direction and rejecting interference from the sides or behind the antenna. The 15 element wi-fi antenna provides over 15 dB of gain multiplying your effective radiated power by 31 , while the larger 20 element wifi antenna provides over 17 dB of gain multiplying your effective radiated power power by Front to back ratio for both antennas is about 22 dB.
Yagi wifi antennas can be rather difficult to build, but it can be done if you measure precisely and cut precisely. The hard mathematical design work for the wifi antennas shown here was accomplished elegantly using a yagi antenna modeler, created by Kevin Schmidt W9CF and Michael Lee. The on-line antenna modeler initially starts with several examples tailored for operation in the amateur radio bands.
One of the best designs is the classic K1FO yagi. By following a few steps, the antenna can be scaled for the 2. The elements list will show each antenna element, from the reflector element 1, position zero mm , to the last director.
Do not use a different metal or a different diameter of metal for the elements, or performance will suffer. Changes in element diameter, metal type, or design frequency will need recalculation and the generation of a new elements list. These dimensions work quite well:. Below is a graphic, meticulously adapted by AB9IL from the modeler, which shows element lengths and positions along the boom, measured from the reflector location zero millimeters.
Note that the driven element is depicted in green, and for the wifi yagi project, will be a folded dipole. Why a folded dipole? It provides a good impedance match to coaxial cable when used as the yagi wifi antenna's driven element. In free space, a folded dipole has a ohm impedance at resonance, but the impedance drops drastically when parasitic elements are brought into close proximity.
Print and use this plan view when building the 15 element yagi wifi antenna. Print and use this plan view when building the 20 element yagi wifi antenna. This high gain wifi antenna can be constructed in a couple of hours and requires some measuring, cutting, bending, and bolting of metal.
Use caution around the sharp edges.
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