Mounting an AP off an I-Beam.

[Dustin Anderson]

I have a few questions to see if anyone has suggestions or more info. I've always been told to not mount an AP to an I-Beam as it messes with the signal. Now, we have a new warehouse being built and the entire ceiling structure is I-Beams. 

So, How far off an I-Beam does the AP need to be to mount? I was looking at trying some of these to see if that works.

https://www.tessco.com/product/201891

I've seen posts of people rigging clamps on the mount plate and putting directly on the beam, but I thought that causes issues. I'm trying to find an industrial solution as we are looking at ~700+ APs and I don't want to have to puts with that many.

[Haydn Andrews]

One of the reasons they would be saying not to mount off the I beams is due to the antenna back lobe and the reflection from the metal beam.

That being said I have seen everything in warehousing, from I beam mounts, direct to the tin roof, inside racking you name it, and in 80% of the cases it actually works, not saying works good, but the devices connect and are usable.

If it was my design I would look at using directional or directional patch antennas in a warehouse rather than omni. I would look to suspend these down from the roof to a height that makes scene for design and wont prevent operations of the shed. But suspend them using a non-ridged cable, to a board of some kind to mount them. This being non rigged cable helps if the AP/ Antenna accidentally take a hit, it can move slightly out of the way.

Like the one in this example in this case it is an omni antenna:

[Dustin Anderson]

Yeah, we were looking at directional for the pallet racking and high ceilings, but then they threw location at us and are now looking at 4800s that are only omni.

[Jurgens L]

I would be very cautious with 4800's in a warehouse environment, as you can't get the version with external antennas Cisco don't recommend them if you need to install them at heights.

 "If the AP is 30 feet in the air, (that is an additional 30 feet farther the signal has to go, “best case”). When configuring coverage for aisles, try to use directional (Patch) antennas on the wall and shoot down the aisles; or use low-gain Omni-directional antennas on the ceiling (such as dipoles) or units with integrated antennas as high gain omnidirectional antennas tend to have more nulls."

https://www.cisco.com/c/en/us/td/docs/wireless/controller/technotes/8-7/b_cisco_aiironet_series_4800_acces_point_deployment_guide.html

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[Leo Laohoo]

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@Dustin Anderson wrote:

Yeah, we were looking at directional for the pallet racking and high ceilings, but then they threw location at us and are now looking at 4800s that are only omni.

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AP4800 doesn't have any option to use directional antenna.

If you're going to choose AP4800, you need to consider uPoE & engage your AM/SE in order to get BLE to work. 

[Dennis Kline]

I have mounted many access points to I-beams, in warehouse environments.  Many of them use internal antennas.  They have all worked well, with no coverage issues. 

 Sometimes you have limited choices on what, where, and/or how you can mount an AP.