Do Sophos "Frisbee" CEILING MOUNT ACCESS POINTS Work FACE UP as Well as Face Down? (AP 15C, 55C, 100C ...)

I posted a similar question in the Wireless forum over a week ago, but got no replies, so I am trying in the general area.

I am replacing my current access points with Sophos AP 100C models, to be run from the current UTM 9.7 software. The AP 100C is designed to be hung upside-down from the ceiling, with the Sophos logo facing down. I assume that a sideways wall mount is also acceptable, although it is not mentioned in the user manual.

I would be easiest for me to place the AP 100C access points on top of high cabinets, close to the ceiling. This means that the Sophos logo would be facing up, opposite from a normal ceiling mount. 

My questions are:

-> Will I get a good wide area signal from the AP 100C if it is positioned high, but facing up?

  • Does anyone know the radiation pattern of the antennas in the AP 100C or has found documentation about it?
  • Has anybody tried laying it on its back on top of a cabinet or other furniture, facing up?
  • Did it work for you?
  • They have radiation graphs for in the brochure ( for newer (APX320, etc) models and I would assume that the construction is basically the same. It's a little hard to figure out exactly what they indicate, but I assume the YZ axis view is what you want, and it looks like 5GHz might be troublesome upside down. In addition, sitting it on top of a cabinet would immediately degrade whatever signal goes "down"  through the cabinet. It would make a lot more sense to wall-mount in a relatively-unobstructed position, in my opinion.

    I'm using an APX320 that's mounted on a hollow-core door with velcro -- long story, essentially wall-mounted -- and it's working well enough for me. (Including off the back/"top" side, but I'm only going maybe 40 feet.) But it has unobstructed line-of-sight to key devices (off of the front) and mostly wallboard between it and other devices. If your cabinets were wood or metal, I wouldn't count on laying it on top working very well at all.

    It really depends on how far you want it to work. If it's WiFi for devices in a small study that will all within 10 feet, maybe almost any placement will work. If the cabinet is hardwood or steel, I wouldn't count on anything working well with it laid on top.

  • Interesting, Wayne.  I've not learned how to interpret those graphs, but your take on them makes sense to me.  Thought I'd run a test at home...

    I have an old AP 10 upstairs in our guest room beside the quiet PC that runs UTM.  It sits upside down on top of an empty dresser.  My home is a two-story house built in 1937, so construction is all wood - no concrete between the floors and all hardwood floors.  Downstairs underneath the AP has a great signal. My spot is an easy chair 40 feet away from the AP.  Through two interior walls (wood & plaster) and the upstairs floor, I get an adequate signal for my usage:

         Service to home:  250/10
         Beside the AP:     38.7/5.9
         Underneath AP:   38.4/4.7
         My easy chair:      8.5/1.9

    Cheers - Bob

    Sophos UTM Community Moderator
    Sophos Certified Architect - UTM
    Sophos Certified Engineer - XG
    Gold Solution Partner since 2005
    MediaSoft, Inc. USA
  • Thanks to Wayne and Bob for their replies. The charts were helpful. You do have to look at them for a while before you understand how to read them. 

    The house is a long, narrow one story; the hallway runs end to end and serves as the "backbone". Two access points are in rooms at each end of the house and two more access points are on either side of the middle of the house. There are walls throughout, but no location is separated from the closest access point by more than two walls. The house is an old wood-framed thick plaster house, not drywall. Well, roughly described, anyway.  

    The access points are currently set to full power on both 2.4 and 5 Ghz bands. Channels were chosen to avoid overlap with each other and with the closest neighbor signals. A WiFi signal strength tool shows good signal throughout, comparable to what I had before.

    Actual usability is less than what I had with the various Apple AirPort type access points, but it is acceptable. By that, I mean that when I take the laptop to the far corners of the backyard, a lot of data is dropped. The Apple AirPorts did not do that as much. 

    This is the "quick and dirty" deployment. I will continue to play with their orientations and mountings and report back if I notice anything interesting or significant.

  • This sounds similar to what I have. Which is why mine is wall-mounted facing the long axis of the apartment. It gives me very good coverage off of the front face -- though it's nearly line-of-sight -- and good coverage off of the back., at the far ends of the apartment. (Off of the back would hit at least three drywall walls and other stuff on the way to where I tested.)

    To be honest, signal "at the far corners of the backyard" is something I would avoid. At one point I definitely turned down the power, though that might've been 2.4GHz before I switched to dual 5GHz. I figure that I got a more secure firewall for a reason and so minimizing my WiFi footprint (vulnerability) as much as possible without impacting daily use is important. I doubt that I would be able to sit on the floor on the far side of the bed and get a good signal, but that's worth it.

    (Even at that, you can see my signal in public areas outside of the apartment and even outside of the building, but I'm not paranoid enough (or rich enough) to try to Faraday Cage the apartment. The signal is spotty there. Actually, it's enlightening that if I call a Lyft and then go outside to wait, my phone sees my home network and stays on it even though the signal is so spotty that it can't update. So I literally have to turn off WiFi to force it to switch to cellular so the Lyft app can get updates. But it's amazing how vulnerable our WiFi is to any of our dozens of neighbors or even someone walking or driving by on the street.)

  • Thanks for the reply.

    I am less concerned about a direct attack on our WiFi network, but your points are valid. The convenience of providing WiFi signals in our backyard and garage outweigh my concerns about other people noticing and attacking the WiFi networks. The neighborhood is separate houses on a dead end street with essentially zero traffic and few pedestrians. All the neighbors are technically clueless.