Wireless Problems with Microwaves

Prodigal

Hi guys,

I'm having some problems at the moment with a project on a company where the TP a MVP7500 is constantly loosing conectivity, with the controller a 2100.

We have made some tests on the wireless and noticed that even ourselves had some hard time conecting and sending code to the controller via Wireless. Even other companies that were working on that company's project were having problems on connecting to theyr Access Points.

The point in that company is that if you run a Wireless networks Sniffer, sometimes you'll get over 30 networks on that point. Other times you get 3-5.

A specialized company on solving wireless problems went there and found there was a strange noise, affecting the wireless. Seems that the building has a motion detection system all over the building (inside and outside in the walls) that uses Microwaves.

We got a Mio touchpad on the field, but that TP must work. Kinda lost a second project with them already, since for the company, the problem is AMX system...

Have you guys had this kinda of problems before, and got a fix for this? Replacing the MVP7500 for a Wired one, is not an option.

Getting out of ideas here.

DHawthorne

Does the MVP have an 802.11G card? If not, upgrade it. It will pull in a signal much better. Also, put an extended range antenna on your WAP, and do whatever you can to move it as close to the panel as you can. You may also want to see if you can shield the panel from the security system ... see where the closest detector is and talk to the security guys about masking it's output in the direction of the panel. It may not be feasible depending on your panel location, but having done microwave base motion detectors back in my security days, I know it's possible ... the question is whether making that part of the field, or turning down the sensitivity would create a security risk. Personally, I have always felt motion detectors to be overrated; they don't catch anyone until they are already inside, when it is usually too late. Much better to detect them before that point.

Prodigal

DHawthorne wrote:

Does the MVP have an 802.11G card? If not, upgrade it. It will pull in a signal much better. Also, put an extended range antenna on your WAP, and do whatever you can to move it as close to the panel as you can.

Thanks for the tip DHawthorne. I'll try doing this, since I think the MVP7500 comes with a B card only and not G. We tried with diferent AP's, altho the same problem ocurred. It stayed a little better by removing the WEP key from our AP, but once, again, this is not an option has you may imagine.


Looking at the Noise scanner program of the team that went to the building, we were aware that that noise was spread all over the room and even in other "interior" rooms (this one has windows, so I'll call it "exterior" room)

The problem is that those detectors are only installed in the interior of the windows of the building. So it is has you said DHawthorne, they are detecting the entrance paths, not quite when they are in already. But the noise created by those sensors goes way thru walls!

I'll try to speak with the security guys, but it's a quite big company, and just to be able to speak with a low ranked person, one has to wait weeks..

Do you know any piece of equipment that we could install by our own that could "clean" an area from those microwaves, or the noise that it is causing?

Spire_Jeff

I believe you can purchase a G upgrade card from AMX for the 7500s. The upgrade also includes an external antenna (external from the card, but still housed inside the touch panel) as I remember.

As for scanning the site for interference, you could look at: http://www.metageek.net/products/wi-spy-24x

This tool works well at giving you a clear picture of all of the traffic in the immediate area and using that information, you might find it better to try a nonstandard channel on the AP (like 2 or 5).

Also, have you monitored the processor to see if it is spamming the touch panel with unnecessary updates?

Jeff

Prodigal

Spire_Jeff wrote:

I believe you can purchase a G upgrade card from AMX for the 7500s. The upgrade also includes an external antenna (external from the card, but still housed inside the touch panel) as I remember.

As for scanning the site for interference, you could look at: http://www.metageek.net/products/wi-spy-24x

This tool works well at giving you a clear picture of all of the traffic in the immediate area and using that information, you might find it better to try a nonstandard channel on the AP (like 2 or 5).

Also, have you monitored the processor to see if it is spamming the touch panel with unnecessary updates?

Jeff

Thanks Jeff.

We've installed some G cards on some 8400 already, need to look for those on MVP7500 then.

I've been thinking on getting one of those for quite along time. But never quite understood the usage of them. In some screenshots, I've seen they give a spectral view of the channels. So you can see the most crowded channels beeing used on that site. But that's basically it right?

Spire_Jeff

I have the first model, and it can be useful in finding problems. It has a couple of views that help, which you use is a matter personal preference. There is the Amplitude view that helps you see the average activity as well as the real time strength of traffic. This one is ok if you have really active network devices. The one I prefer is the Spectral view. The spectral view allows you to adjust the time frame from 15 seconds to one hour of data being displayed on the chart. This really helps me visualize the traffic a lot better in my head.

If you are having problems throughout the day, but nothing that is making sense, you can setup a laptop with this device and let it run for the whole day, and the scroll through the data looking for odd interference.

Jeff

P.S.
I think you can download the software for free and they have some recordings available for download as well to help you understand what the software shows. I could even post a REALLY noisy recording of my own if you wanted

vining

Is this panel used in a single room? Is this WAP part of a larger WI-FI network or is this WAP strictly for the room and using a seperate SSID?

If it's used in a single room I would recommend using a single WAP with it's own SSID and obviously put the RF channel as far from everything else as possible although it sounds like that's not possible. I would also consider what Dave suggested and use a high gain antennae although the name is some what miss leading because it really just focuses the radio waves to specific patterns. Again this is if the panel doesn't roam because if it does it may make your problem worse in some areas. If you look for directional antennaes and put your WAP at one end of the room so the the entire room is in it's directional field of view you may be able to increase your MVPs signal to noise ratio enough to drowned out the RF noise and chatter.

MVPs also don't like to hand off to other WAPs on with the same SSID so if it's part of a larger SSID network you may be caught in the Bermuda triangle of coverage where multiple WAPs look good and at the same dbmv levels and the MVP just gets confused and connects to one then another and so on which is why a single WAP/MVP network might make things behave.

If you take aluminum foil and wrapped the motion detectors with it when no one is looking you'll solve the microwave problem. Ok, don't do that, you might piss the security guys off.

DHawthorne

vining wrote:

If you take aluminum foil and wrapped the motion detectors with it when no one is looking you'll solve the microwave problem. Ok, don't do that, you might piss the security guys off.

Actually, that's not far from how it is actually done. The sensors all come with a set of foil adhesive strips that you stick to the inside of the lens to mask areas from the microwave beam.

Prodigal

Spire_Jeff if you can, post an example of a spectral view please, would apreciate to know how I could work with it.


vining, in this case, the panel is used in a single room. It won't go out of there.

Unfortunatelly, the technical rack, where everything is installed, is in the side of the room, at the middle of that wall. Lets say the room is
Side A: 10m
Side B: 4m

The rack is on the middle of Wall A, so it's quite impossible to use a directional antenna, since I would have 5m to each side. (can't move the WAP either)

Although I really liked the aluminum foil idea. It will be excelent to debug where the problem comes from!

Thanks

yuri

why can't you move the WAP?
Get a Power over Ethernet injector, put another UTP cable to somewhere in the middle of the room, and connect your WAP (hoping it's PoE enabled )

Spire_Jeff

Here are a few scans. The higher res versions are downloaded from the site and are created using the newer scanner. (I'd love to get a new one). The lower res pics are a scan I ran on a VERY busy network. You can see the various Zigbee traffic as well as a couple of WiFi streams.

Prodigal

Hey guys. I was around reading my CCNA book (geez..) when I got myself on to 802.11a

Is it possible to get a 802.11a wireless card for a Modero Touch Pannel? I think it would fix my problems in this room

Diferent frequency, and the distance is not a problem.