
Rebuilding, Testing and Documenting Self-Made Wi-Fi Antennas - davesailer
http://www.notechmagazine.com/2017/01/rebuilding-testing-and-documenting-self-made-wi-fi-antennas.html
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Animats
Unfortunately, there's no real testing. Just pictures.

Antenna testing is usually done in a big open flat space, with gear that can
measure field strength. Do this some place where you can't pick up any other
WiFi signals. Some WiFi gear lets you read signal strength from software, and
you need something that can do that. There are some videos online of people
measuring antenna patterns at ranges of a few feet, but that gets you strange
near-field results. You need distance for this, like a hundred feet or so. The
antenna is usually placed on a nonmetallic turntable that can be rotated, and
the idea is to generate a chart of signal strength vs. angle.

Here's an test of a "cantenna" in a real antenna testing facility.[1] He also
builds one with the same dimensions out of copper sheet, for comparison, and
also compares with simulated results. Antenna design used to be a black art,
but now there are software tools to help with design and evaluation.

The ARRL Antenna Book has good advice on how to build antennas cheaply.

[1] [http://www.antennamagus.com/blog/593/pringles-cantenna-
measu...](http://www.antennamagus.com/blog/593/pringles-cantenna-measured-in-
an-anechoic-chamber)

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rra
hi,

I'm the author of the project. To answer questions about testing and which
design is 'the best': The project was produced in a cultural context so I had
no access to specialized measuring equipment or techniques. What I've done is
to run side by side comparisons, so I only have circumstantial evidence.The
method was to compare the antenna or reflector against the stock antenna on
the same dongle and seeing which one resulted in most SSIDs showing up in
wavemon. That being said, the big difference between most diy antennas vs the
stock antenna is that the diy antennas basically work on the principle of
directionality, meaning increased gain in a narrow cone. So you have to point
your antenna at the signal source for a higher gain.

Which one is the best really depends on the use case, materials available and
time you want to invest. I've found the biquad in the sardine tin[1] to be the
handiest for all-round situations and use it frequently. It is directional,
but has a wider field of view than other directional antennas. Compact design,
sturdy build quality. Not too difficult to produce and sardines combine great
with pizza or pasta. Here is some more info on that type of design[2]. If you
only have access to dongles without a detachable antenna I'd recommend using a
wok or some other parabolic reflector.

[1][http://roelof.info/projects/(2014)Pretty_Fly_For_A_Wifi/IMG_...](http://roelof.info/projects/\(2014\)Pretty_Fly_For_A_Wifi/IMG_0963.png)

[2][http://pe2er.nl/biquad/index.htm](http://pe2er.nl/biquad/index.htm)

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kstenerud
Consider using jpeg instead of png for your images. You'll get a 5x-10x
bandwidth reduction, especially for such an image heavy site.

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anilgulecha
The link should change to
[https://roelof.info/projects/(2014)Pretty_Fly_For_A_Wifi/Pre...](https://roelof.info/projects/\(2014\)Pretty_Fly_For_A_Wifi/Pretty_Fly_For_A_Wi-
Fi_booklet.pdf)

Also a question to the community: which is the most bang-for-the-buck DIY
antenna: does not need millimeter accurate measurements, increases signal by
~2x, and ideally small and stow-able.

Most common usecases are extending signal on 3g/4g USB dongles, and extending
wifi signals at home (to one side at the expense of the other).

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pizza
Antenna design seems like an obvious target for 4D-printing.

