WAP and 881W on a ceiling?

[johnshaw]

I just read the following out of the wiki......https://tech.lds.org/wiki/Meetinghouse_ ... e_firewall

Placement in offices or cabinets should be avoided whenever possible. The meetinghouse firewall can be placed on a shelf or surface mounted to a wall or ceiling. To optimize wireless avoid placing the device near a lot of metal and position the antennas vertically (up or down).

Is it acceptable to mount the Cisco 1041 on the ceiling in a meetinghouse. For example, a traffic hallway going around the building. That gets us at least a bit closer to the center of the building if it is acceptable?

[russellhltn]

The 1041 WAP is designed for ceiling mount. I'm wondering how you mount a 881W firewall to a ceiling.... (It's also no where near as attractive.)

[harddrive]

The 1041 WAP is designed for ceiling mount. I'm wondering how you mount a 881W firewall to a ceiling.... (It's also no where near as attractive.)

Russell, I totally agree that mounting the router on the ceiling isn't as attractive. Also to me it should be locked away so that no one can mess it it.

I thought about mounting the 1041 on the drop ceiling, because that is the connection that comes with it but the issue that I have is that they could become a target for the 9 to 14 years old. So in the one building that I put them in, I hide them above the ceiling tiles.

This morning I was thinking about it and I could have put it off the drop ceiling in a corner where no one would perhaps see it and not out in the middle of the hallway. This would give me better coverage in the building, because the foil on the insulation and on the ceiling tile would not hamper the signal.

If you want to mount them to the ceiling tiles then go ahead, but I would put them somewhere that they are out of the main stream of traffic and the kids don't use them for targets to see who can touch them or throw stuff at them.

Just my 2 cents worth.

[russellhltn]

I hide them above the ceiling tiles.

You might want to have them "face down". I don't know, but suspect that the units may angle the antenna pattern "downward" since energy angled upward is "wasted". If you lay the unit on it's back, you may have decreased range.

[jdlessley]

The orientation of the unit does not matter so much as does the orientation of the antennas.

The antennas of the 881W are vertically polarized omnidirectional (see the Cisco 880 series data sheets). Because the antennas are omnidirectional there is no down tilt to the vertical beam width - according to Cisco. There is just as much angle up as there is angle down.

I would check to make sure the antennas are oriented vertically to the direction of the desired reception and range.

[russellhltn]

The antennas of the 881W are vertically polarized omnidirectional.

Except I was talking about the 1041

Because the antennas are omnidirectional there is no down tilt to the vertical beam width - according to Cisco. There is just as much angle up as there is angle down.

I know I've read articles about 2 meter antennas where they talk about the "angle of take-off" and how antennas that are good for home use are not good for repeater use because of that issue. Not sure why that same concept can't be done at 2.4GHz. Then again, maybe "down tilt" is something different - having the installer deliberately tilt the unit. That's not going to work on a omni. But that's not to say the antenna designer couldn't do something.

[jdlessley]

Except I was talking about the 1041

Cisco does not provide any information about the 1041N antenna pattern directly other than to say "horizontal beamwidth 360°". By their definition at their Design Technotes page on omni antenna vs directional antenna I surmise that the integrated antenna is omnidirectional and vertically polarized. With the integrated antenna omnidirectional and vertically polarized, the best radiation pattern is obtained with the unit attached to a horizontal surface. Since Cisco does not specify or mention an up or down orientation I would assume that the radiation pattern is symmetrical and that either orientation will result in the same performance.

I know that is a bit of assuming. Based on their own information or lack thereof that is the best I would be able to come up with without doing any testing.

[russellhltn]

Well, I'll defer to the two microwave experts, but I don't understand why that basic tutorial claims that you can't point the lobes downward with a omni. Because I've seen other articles that talk about doing exactly that with a single vertical.

Bottom line, the RF engineers would probably expect to see receivers "below" it, not a "above" it. I just think it's wise to mount it with that in mind.

[Mikerowaved]

Well, I'll defer to the two microwave experts, but I don't understand why that basic tutorial claims that you can't point the lobes downward with a omni. Because I've seen other articles that talk about doing exactly that with a single vertical.

We're kind of getting a bit off topic here, but a typical 1/4λ or 5/8λ ground-plane antenna has a natural tilt to the surrounding pattern because of the additional reflections off the supplied ground. This tilt can be made more pronounced or even nullified by manipulating the antenna's relationship to the ground (and other things). Because low-end WiFi antennas found on this type of gear are generally 1/2λ dipoles (printed or external) that do not required a ground plane, this type of electrical tilting can't easily be done. You can physically tilt an external antenna to make one edge of the "doughnut" shaped patter better cover the "hole" found directly underneath it, but the result will be the other edge of the pattern will be elevated, probably making overall coverage worse.

With that in mind, these ARE low-end, low-gain antennas and as such have a doughnut shaped pattern that's very round and fat and will not have a well defined "hole" under them. (One definite advantage of using a lower-gain antenna.) Nor will they care much if they are mounted right side up or upside down. Only if you switched to a high-gain WiFi antenna do you have to be at all concerned with these things.

Finally, IMO the 1041N looks enough like a typical smoke or motion detector commonly found in public buildings that I don't think kids will show much interest in them at all, but that's just my take on it.

[johnshaw]

As an interesting note, my stake is building a prototype meetinghouse and the new Cisco 1041Ns will be placed on the ceiling. In all the plans I never assumed it would be in the hallways, but I was in the building last night and there they are mounted on the ceiling. They typically build the standard plans from their experience with these prototypes, so we'll see how it goes.

FM had 2 major concerns
1. Kids will jump up and touch/hit/whack at... as has been stated on this thread
2. The Cisco brand is a target for theft

He decided to go ahead and mount them and see what happens

so I'm going forward with mounting them on ceilings in my buildings where I have no-drop ceiling... (I only have drop-ceiling in 2 of my 9 buildings)