Omni antenna or not for this open room? 400 users.

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I was wondering if omni antennas are fine or should I switch to patch antennas? I have meeting room that is 110ft x 110ft with a 20ft. ceiling. I have up to 400 users just using the access for browsing only (no video.audio, etc). Mainly text for business related info.

I was hoping to use just two 350APs and hang them right in the middle of the room although I could mount the on the side walls somehow and use patch?

Anyone see any issues with using the default omni and just two 350 APs?

Thank you,
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jacob600

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Posted 5 years ago

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Brian Powers, Champ

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A few things.

The AP radio profiles are limited to 100 users. So you would be maxing out each AP completely if there were indeed 400 devices in there trying to connect. Which would make for a pretty poor wireless experience, I'd imagine.

But for coverage wise, I'd separate the APs vs. placing them close together. This would help load balance users across the APs somewhat.

Directional antennas would let you somewhat control the areas that the APs radios cover, but is a possibly added cost if you dont already have patch antennas for the 350s.

Whichever option you go with, I'd be sure to customize the radio profile and see about turning on load balancing and band steering to share the load of the clients.
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jacob600

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100 users??? I thought it was around 200 users, at least "Radius authenticated users" and based on what one of the Sales guys has stated. How about four 141s, would that work?
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Brian Powers, Champ

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So yeah. 100 users per radio. 200 per AP. It matters not the authentication type as its a hardware/software limit of the code.



But understand that wireless is a shared medium. Skim through this PDF, http://www.aerohive.com/pdfs/Aerohive...

It has some great pointers in designing for areas of high/extreme high density.

Four 141's would in this situation would give you 7 actual radios of usefulness. 4 a/n radios and 4 b/g/n (but with only 3 non-overlapping channels 1, 6, 11), you'd have one channel used twice which would put clients connected to that channel in the same frequency space all sharing the same contention domain and access to Tx/Rx without proper separation (which is hard to do in a auditorium type area).

If your site is truly 12,100 sq. ft., and we simply divide 4 APs by that. Each one would service ~3000 sq. ft. Thats actually plausible and with a little bit of adjusting (of AP power levels and ensuring proper channel separation), I'd say the 4 141's would be a better fit even with omni-directional antennas.

As for the comment about Sales guys, sadly, their technical qualifications are usually lacking and are just trying to push product out the door.
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jacob600

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Thank you very much for the advice. I will go with four 141s. I was already thinking about the dimensions. I was planning on cutting the wattage in half (17dbm) and probably enable the High Density Wlan Settings. I will also hang them in the middle of the room from the ceiling in a linear fashion, right down the middle. Kind of "cutting" the room in half if that gives you a good visual Sound about right to you?
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Brian Powers, Champ

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If possible, I'd place them in quadrants. So, say the area is square with no obstructions. If you were to divide it up evenly (an x and y axis so to speak), I'd put an AP in each quadrant.

I believe this would best assist in helping balance the users (when there's a full house). Where as the band steering and load balancing from the radio profile will help balance users in the situation where it isint full, but say one quadrant has all the users.
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Crowdie, Champ

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As you have an open area I would utilise directional antennas aimed down at the ground.

If you try to utilise omni-directional antennas, particularly if you require more than three access points, you will get large amounts of co-channel interference.

The directional antennas should also help avoid "sticky" clients that do not want to roam from one access point to another.
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jacob600

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I will research the Directional Antennas. I know Aerohive only has two I don't want it to get too clumsy. I guess these will be 3rd party.

In the meantime, I'll turn down the wattage while I use the default antenna kit (omni). If you have a link to recommened Directional Antenna, I would love to see it.

Thanks again everybody.
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Crowdie, Champ

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Try to find a local distributor for MARS Antennas (http://www.mars-antennas.com).  MARS Antennas are in Israel but manufacture the AH-ACC-350-ANT-5 antenna that Aerohive OEMs - if you look at the back of the ACC-350-ANT-5 you can see the MARS sticker.  MARS have an excellent range of external antennas and mounting kits.