The lips cut down radiation from the rear lobes of the biquad by about 6 dB Note that they are only required along the main edge axis of the reflector. The reflector's 'lips' are 30 mm high, and serve to reduce coupling into the mounting bar. Aluminum can be used if soldering of the rigid coax is not required at the feed point. I used Printed Circuit board scraps for the 110 x 110 mm reflector, but it will be just as effective if made out of sheet brass or copper. You will lose about 3dB of gain when using the horizontal mode, as the biquad's radiation pattern is a better match for the dish's oblong shape when vertical polarization is used. To make it horizontal merely rotate the feed by 90 degrees. The feed is oriented for vertical polarization in this photo. But they are hard to feed because the f/d ratio varies from about 0.5 in the vertical axis to 0.8 on the horizontal axis.Īdditionally the spacing between the feed 'slot' and the feed mounting bar is small (about 55 mm), which is less than a half wavelength at 2.4GHzįailure to couple efficiently to the dish's wide aperture, or to minimize radiation into the mounting bar, will result in poor gain and/or significant sidelobes. They have superior sidelobe performance when compared with a wire grid antenna, reducing the chance that somebody off of the axis of your link will be able to interefere with it. The Primestar dishes are high gain, low cost, parabolic reflectors with an offset feed. Low sidelobe 802.11b BiQuad feed for Primestar dish
(15-17dBi) Slotted Waveguide WLAN antennas
Link to my tutorial 'Antennas Enhance WLAN Security' from, October, 2001 Miikka Raninen (OH3GPJ) builds and tests the biquadĬlick here for details of Mark LaPierre's 1100ft link through forest canopy, and comparison with Pringles can performance.Ĭlick here to link to Koen Weijand's page on using an 18inch dish and feed details *** Engadget builds and tests a BiQuad/Primestar combination *** Want to master Microsoft Excel and take your work-from-home job prospects to the next level? Jump-start your career with our Premium A-to-Z Microsoft Excel Training Bundle from the new Gadget Hacks Shop and get lifetime access to more than 40 hours of Basic to Advanced instruction on functions, formula, tools, and more.Trevor Marshall BiQuad 802.11b Antenna 11dBi, wide band Check out Danilo's post for more details and photos. Danilo says his connection speed "went from erratic to 5.5 Mbit," so if you need a boost, it's definitely worth a try. Please enable JavaScript to watch this video.
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