15 Element Wi-Fi Yagi

Okay guys and gals, it's done. After lots of e-mails asking about a good Wi-Fi antenna that is simple to build and still beats the cantennas and wok-tops: http:

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. Gain is around 15 dBi, and it is made of wood, wire, and a pigtail.

Enjoy!

Phil

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Reply to
ab9il.worldwide
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Nice but not enough info to actually build one. There's no detail on the driven element. Some general comments:

  1. The center of the Wi-fi band is 2442 MHz, not 2450 Mhz
  2. Round the ends of the elements. Don't square them off. The cut length should be to about 2/3 the radiused end. See Antennex yagis for what I'm talking about. It increases the usable bandwidth dramatically with no loss in gain. The wire guage you're using will result in a rather narrow bandwidth. I prefer 1/4" copper water pipe.
  3. When I click on the right hand antenna pattern image, I get 404 not found.
  4. The directivity pattern looks really odd (if not wrong). It should look something like this:

Note that for 14.5dBi gain, the commercial antenna is about 462 mm. Yours is 419 mm long. Close enough.

  1. What is the boom made from? It looks like wood. Hopefully it's not conductive or all you calcs are wrong. With a conductive boom, the element length is measured to go around the outside of the boom. Wood also has a bad habit of absorbing moisture. I watched a 440MHz yagi that I build from a 2x2 fir boom slowly change vSWR pattern over several months as the wood absorbed and released moisture. I don't expect much of a problem with your size boom, but it is something that you should watch for.
  2. Oops. I didn't see the "next step" at the bottom of the page. May I suggest you make it an obvious button that's duplicated at the top of the page. The 2nd page details the construction, but doesn't show how the pigtail is attached, whether a balun is used, and whether any matching is required for what is normally a 200 ohm folded dipole.
  3. I can feed the design into 4NEC2 and see what it looks like, but don't have the time. (sorry).
  4. Have you done any measurements? Even a Netstumbler comparison with a known reference antenna is useful.
  5. You might wanna post it to rec.radio.amateur.antenna for additional comments.

Good luck.

Reply to
Jeff Liebermann

At wifi frequencies, the dimensions are within the range of those "Internet" PCB manufacturers. Is a PCB trace too thin to make an antenna?

Reply to
miso

Well, yeah. I think you mean the tolerances, not dimensions.

What PCB trace? Are you thinking of building a PCB driven element or balun? It can easily be done. For example, here's a 900MHz log periodic PCB antenna:

Note that the PCB material is polysulfone, not G10/FR4.

Much cheaper are those made by Ramsey for various bands:

These are G10/FR4.

The width of the trace acts exactly the same way as the diameter of a rod element in a traditional yagi antenna. The fatter the element, the greater the bandwidth. All a too narrow a trace does is narrow up the usable bandwidth.

Reply to
Jeff Liebermann

Actually, I did mean dimensions. Most of the "internet" PCB fabs limit themselves to about 22 inches in length

Reply to
miso

Phil, Do you have a photo of the coax connection to the Yagi? Thanks buddy!

Pete

Reply to
Knight

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