Meraki MX68CW poor wireless coverage

[MR_Winter]

We are currently rolling out the MX68CW-WW devices in our smart virtual workspace project and we are getting constant complaints about poor wireless coverage. I'm currently running a MX67W and my wireless coverage is what i would expect from the device. I have checked the data sheet on both devices and according to the documentation they are running the same wireless hardware. 

We have arranged a few site visits to investigate the problem and we have found that there is a serious wireless coverage issue. We run the following command "netsh wlan show interface" to determine the signal strength and from within 2 meters the signal strength has already dropped down to 70% and this gets worse with each step you take away from the device. 

We have done the standard wireless checks to ensure there is no noise or interference on the specific channels that the Meraki is making use of. 

Is this the expected range of the device or are we dealing with the hardware fault?

[ww]

70% on 2 meter in a open space?

did you try to manually set a dbm to see if you get any improvement?

are antenna's mounted ok?

Is cellular  also used?

On a mx68w

i see 91% on 2 meter and the device is in a closet.

87% with a addional wall on 4 meter.

[MR_Winter]

Hey WW, 

Thanks for the response, 

Are the Antenna's detachable, i had a look and wanted to unscrew them and attach them again but they appear to be permanently fixed. I decided against trying to unscrew them more in case i damaged the device. 

We are not running cellular on this device

[PhilipDAth]

It's starting to sound like you have some faulty units.

Is there anything nearby that might absorb or attenuate the signal?  Like fish tanks, metal wall framing, etc?

[MR_Winter]

Hey PhilipDAth

Thanks for the response, in the picture below you'll see the MX unit and then my laptop and you can see there is nothing in between. 

Are there additional commands we can run to try and determine the health of the device?

During the test we were all connected to the 5Ghz band and we wanted to know if there was a possibility of switching off the 5Ghz network and testing the coverage on the 2.4Ghz band but this doesn't seem possible. 

 

[CptnCrnch]

As far as I know, support can disable 5GHz Wifi

[ww]

At your picture your on the 2.4ghz

At the laptop network card (advanced) settings you can force 2.4 of 5 ghz. 

I guess the 68cw antenna is not detachable as it comes pre-installed.  

[MR_Winter]

Yes i disabled 5ghz on my network card, the user has a Mac book and i have no idea where to amend that setting which is why i was wondering if it was possible to disable certain bands on the device itself.

[Bruce]

I don't believe that the sort of loss you are seeing is that surprising. The RF signals drop off really quickly close to the antenna. In the first 2 meters (@ 5.1GHz) you'll see loss of abut 52dB, extending this out to 4 meters and the loss is only 58dB. Think of a circle one centimetre away from the antenna, and consider its circumference. Now consider the circumference of a circle two meters away from the antenna - there is a huge difference.

The power transmitted from the antenna is distributed roughly evenly around that circumference at 1cm radius, and the same power is distributed roughly evenly around the circumference at 2m radius. The circumferences are 0.062m and 12.56m respectively - it is a huge difference.

Now some of the features we have in wireless access points, especially maximal radio combining (MRC), allow us to receive multiple signals and combine them to achieve a better overall signal, but ultimately the losses close to the wireless access point are huge.

I know I haven't really answered your question, but I hope it helps in understanding that the losses you are seeing are not really surprising (in fact I'd say only 70% is good).