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OPK

WiFi 2.4GHz Yagi Biquad Antenna with reflector and fixed element distances

by OPK Oct 1, 2018
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Hi, would you be able to upload a version which uses a lower frequency (2370mhz), this would be greatly appreciated by the FPV community, as its outside the Wifi band, and much cleaner for our use.

Hi, Feel free to edit my design files, I have uploaded all files incl. the ipt which can be edited in eg Autodesk Inventor.

What a logical design progression, such a neat solution :-) I have used sticky copper tape (or Aluminium ducting tape which is also self-adhesive) to line the backplate reflector so I need a couple of spacers to allow for the lack of a front cover. Be good to add a picture of how you connected your coaxial feeder.

Hi, I also used the sticky aluminium tape, but on purpose I wanted it to in-between the 2 back plates for protection of the fragile tape. Besides that, it look better ;)
One picture shows the close-up of the coax solder from the front, you cant see the coax though :)

How do you make the bends in the copper wire? Mine, no matter what ive done, come out rounded. Not at a 90 degree angle. thanks!

I grip the wire with pliers that have a flat side (most do) and then I use the workbench to press/fold the wire towards the pliers.

The best tip I can give if you want to dive into antenna building, is to invest in this swr meter: "N1201SA UV RF Vector Impedance ANT SWR Antenna Analyzer Meter Tester 140MHz - 2.7GHz". You can buy it from the usual places... I bought mine for 140 Euro or less and for sure it will open your eyes :) I asked Andy to test it, but he never got around to it. These two videos will give you a solid impression though. Ah yes, also buy a 20 Euro calibration kit with it (3 SMA connectors, one open, one closed and one 50 ohm). My N1201SA needed calibration before use (was very easy).

Nice work! I like the tripod mount integrated with the reflector.

Thanks - the design bases was excellent :)
It took a little time to calculate the element distances as you want the distance to the copper; not the plastic parts. Hence I think the "step-wise" guides fit only one element at one location - makes it "fool" proof.
I also made many driver elements (sizing from 29-to-over 31.5mm) to move the frequency towards channel 11 (2462MHz) for my use case, but the frequency did hardly move - I guess then all measurements need to me changed. In case of a normal or double bi-quad, that always works...

wow this is what i wanted for long so that the elements wont move did you use super glue? the spacing i did was between the copper elements and ignoring the plastic in between the measurement, kinda mess up with the spacing a little bit by couple of millimeters and what dbi do you think it is? i

I did use superglue, but any glue would work. How many dBi? Difficult to say as I could not measure it. Based on other antennas I measured, I would estimate (!) it at 16dBi -ish.

thanks, i think andrew said that his pcb biquad yagi is around 18dbi but deception here https://www.thingiverse.com/make:327272 measured it an anehoic chamber about only 10-11dbi with mesh reflector, maybe thats why the mesh reflector and the length of the coaxial cable lessen the dbi. can i place the aluminum tape on the front of the reflector like i did? does your's add an extra millimeters? and last sir can i use the reflector that reallybigteeth created, coz i use that in my print and the center circle for the coaxial hole is smaller are yours and his are the same in spacing but yours is just bigger coaxial holes?

Biquad Yagi Antenna - 2.4 GHz

I tried to give a realistic dBi number, but without really measuring, there is not much point, is there? I noticed that the antenna I build has a better swr than the one measured in the chamber, but after many antenna builds, I must admit that this is a bit of dark magic - at least to me.In my design you should not put the aluminium tape on the front. It will throw the measurements off. You cannot use the other reflector because mine has the reflector against the guides, while his sit "on" the guides. Also I got the best results with a closed reflector instead of a reflector element.

so closed reflector- is that the aluminum tape connected or grounded to the coaxial rpsma connector? heres what i printed months ago with a help from RBT, i just got a vistumbler and no special swr tools to test to... just a hobbyist thing, https://www.thingiverse.com/make:520274 so if i try using your guide it will be off the 19mm measurement for the backreflector, is your backreflector holes are the same with RBT backreflector in distance and diameter except the middle holes for the coaxial cable or rpsma plug
im planning to use your build anyways so its more rigid and more precise on the elements spacing and just to clamped it on my cheap smartphone tripod.

Biquad Yagi Antenna - 2.4 GHz

Nice build and neat soldering! My reflector is indeed connected to the coax ground, but that or an isolated reflector made no difference at all...