aplocher
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Pi Zero-W placement for ideal wifi antenna reception

Sun Aug 13, 2017 8:31 pm

I'm putting the Pi Zero-W in a little handheld case with a 7" LCD.

Is there a recommended position (relative to the wifi router it's connecting to) for the board? e.g., Should the antenna side (with the HDMI/USB ports) be up, down, left, or right? Does it matter if I have the back facing forward (towards the router)?

What about relative to the 7" screen? Any recommendations there? Ideally I would attach it somehow to the back of the screen, but I would assume there might be some interference.

Of course the placement to the router isn't going to be exact, since it's a handheld (portable) device. But I'm just trying to determine a base configuration and it's good to know for future projects as well.

Thank you!

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elkberry
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Re: Pi Zero-W placement for ideal wifi antenna reception

Mon Aug 14, 2017 6:27 am

As always, wireless sending and reception heavily depends on your specific setup and surroundings. There ain't such a thing as an ideal setup, much the same as there isn't a pot of gold at the end of the rainbow. Even your body with so much water is a terrible thing to have around radio systems. Test your setup to see how it reacts. If you need that ideal reception, use Ethernet.
From ZX81 to Raspberry Pi, but wait ... where's the 7805 gone?

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Burngate
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Re: Pi Zero-W placement for ideal wifi antenna reception

Mon Aug 14, 2017 4:50 pm

WiFi at 2.54GHz has a wavelength of about five inches, so an antenna shorter than about 2½" (half a wavelength), as on Pi zero W, is going to be fairly omnidirectional.

But anything conductive within a wavelength or so, or a foot or two, is going to affect the radiation pattern, and could even act as a reflector, reversing the pattern. That includes the Pi itself, the LCD and its surround.

So there's no magic set of rules: just moving the Pi a couple of inches could change or reverse the radiation pattern.

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bensimmo
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Re: Pi Zero-W placement for ideal wifi antenna reception

Tue Aug 15, 2017 11:27 am

You could try fitting it and mapping the reception in various positions and setup.

Report back what you find.

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chrisoh
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Re: Pi Zero-W placement for ideal wifi antenna reception

Tue Aug 15, 2017 11:41 am

Anecdotally I've found the Pi3 to perform better when orientated vertical, no idea why, as the 'antenna' is tiny.
Pi Zero W I've found to be quite omni-directional as Burngate said. When placed next to a brick outer-wall, orienting the antenna away from it improves the signal somewhat, I imagine that would apply to any radio antenna in close proximity to a brick wall.

Btw, the unicorn jokes are a getting beyond tedious now.
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jahboater
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Re: Pi Zero-W placement for ideal wifi antenna reception

Tue Aug 15, 2017 1:41 pm

chrisoh wrote:
Tue Aug 15, 2017 11:41 am
Anecdotally I've found the Pi3 to perform better when orientated vertical, no idea why, as the 'antenna' is tiny.
I believe its a dipole. So if the antenna(s) on your router are vertical (so the signal is vertically polarized) you should in theory get a stronger signal with the Pi's dipole vertical and parallel to the routers antenna.

The Pi Zero W's antenna is more sophisticated, but it wouldn't surprise me if the longest edge of the triangle should be parallel to the routers antenna. Just a guess, and ignoring all the other issues mentioned with a 2.4GHz signal.

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chrisoh
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Re: Pi Zero-W placement for ideal wifi antenna reception

Tue Aug 15, 2017 1:59 pm

jahboater wrote:
Tue Aug 15, 2017 1:41 pm
I believe its a dipole. So if the antenna(s) on your router are vertical (so the signal is vertically polarized) you should in theory get a stronger signal with the Pi's dipole vertical and parallel to the routers antenna.

The Pi Zero W's antenna is more sophisticated, but it wouldn't surprise me if the longest edge of the triangle should be parallel to the routers antenna. Just a guess, and ignoring all the other issues mentioned with a 2.4GHz signal.
Makes sense, yeh. I remember twiddling the antennas on my first WiFi router with this alignment in mind after reading up on it, really can't remember the outcome though, it's been too long. I think I surmised that there may be too many other variables involved in a residential setting to see notable differences in signal and got on with life :lol:
Alignment aside, attenuation with proximity to objects and incidence angles seem to be much more pertinent (at least in my case) when trying to go from disappointing to decent-enough signals.
Raspberry Pi 3 model B Idle @ 250mA
  • HDMI +200mA
  • Minecraft 1.9 Server +100mA
  • 2.4Ghz dongle +20mA

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elkberry
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Re: Pi Zero-W placement for ideal wifi antenna reception

Tue Aug 15, 2017 3:52 pm

There are these kwel colored and flexible antennas with the two 8pin connectors at each end. Available in different lengths, to match with where your access point is. Very fast.
From ZX81 to Raspberry Pi, but wait ... where's the 7805 gone?

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