Cisco Meraki MR86 - EMI

[MichaelMS]

Hello everyone.

I am working with a customer looking to have Cisco Meraki MR86 implemented outdoors in parking lots mounted on light poles.  I am designing the physical infrastructure (underground conduits, cabling and mounting the AP's to light poles.  I am physical Layer-1 designer and not a data network engineer.

We are looking to mount these about 10-15' from the ground, but not sure how much below the actual light fixture to avoid EMI interference.  I am thinking i would need to know what type of fixture is in place and what type of voltages or current is running the light fixture? The datasheet mentions these devices are weather proof and include a pole brackets, but believe some type of PVC enclosure might be a good idea to place the MR86 into.     

Would appreciate any comments if you have done this type of solution in the past.

[PhilipDAth]

300mm away from the antennas is usually fine.

And for bonus points;

I will assume this will mostly be using 2.4Ghz to increase coverage.  2.4Ghz uses a 122mm wavelength.  You want to avoid interference sources being placed a multiple of 1/4 of the wavelength away from the antennas (31mm, 61mm, 92mm, etc).  This is also why the length of a 2.4Ghz antenna is usually a multiple of a 1/4 wavelength (maximum gain).

You also want the antennas spaced out from metal light poles (in case you are not using concrete or wood), to prevent the metal light pole from soaking up a lot of the radiated RF energy.

I think it is pretty common to put them above the light fixture.

But once you are 300mm away the impact is so small you can ignore it.