Predictive Modeling of MR84

[gunnyreinhard]

We are doing predictive modeling in TamoGraph with an MR84 with the ANT-20 omnidirectional antenna. If I mount the AP Flush against the ceiling then the horizontal plane or zero elevation of the antenna is parallel to the ceiling. If I wall mount the antenna then the horizontal plane is now 90 degrees correct?  

HorizontalVertical

[GIdenJoe]

Hi,

The M74 and 84 are usually wall mounted.
So the antenna are vertical in this case.

In that case your azimuth signal spread (the almost perfectly round one) will be seen from the top view and your stretched view from the side

If you would ceiling mount the AP so the antennas stick out horizontally your Azimuth would be viewed from one of the side or frontviews.  The top view will show an orientation of the elevation pattern (the stretched one)

[MerakiDave]

@gunnyreinhard what @GIdenJoe said is correct, when an MR74/84 is wall mounted and the ANT-20 elements are pointing straight up/down, the E-plane is perpendicular to the ground (vertical polarization).  

[gunnyreinhard]

@MerakiDave and @GIdenJoe 

Thank you for the advice, I wanted to confirm a 3D model of both antenna patterns. This represents an MR84 with ANT-20 mounted vertically. Thank you both for the help.

2.4 Antenna5 Antenna

[GIdenJoe]

Yeah, the 3d makes it even easier to view.

Do mind that your covered distance will be en exaggerated version of the antenna plot like in the previous pictures you shared.
For every 6 dB you drop you halve the distance covered.

So when the software gives a predictive heatmap you'll see the inward ripples better like on your 5 GHz antenna pattern.  Especially if you put the antenna horizontally you should see a gap of coverage in the four diagonal directions.

[gunnyreinhard]

@GIdenJoe so looking at those models with the antennas and AP mounted vertically, those look correct?

[MerakiDave]

@gunnyreinhard yes, those predictive plots are correct for the vertically oriented omni. 

Keep in mind as @GIdenJoe mentioned, the RF rule of thumb is that outdoors with no obstructions, every plus or minus 6dB corresponds to roughly double or half the range, respectively.  Indoors it's typically +/- 9dB but varies for every deployment and best to confirm during a site survey.  Outdoors, free space path loss is the more significant loss factor, and you'll typically see that hold true (double the distance = 1/4 the power).  

Also keep in mind which 5GHz band you're testing/surveying with, as UNII-3 channels will attenuate faster then UNII-1 channels.  May not make much of a difference if you're designing around the least-capable client device.  You may not need to split hairs, but just in case it comes up, like if you're doing longer distance bridge/mesh links then plan/survey with appropriate channels.  I typically see this more indoors, for example the signal from the AP 3 rooms away might be 10dB weaker on channel 157 versus channel 40.  Generally speaking, choose a channel in the center of the band you are surveying for.

[gunnyreinhard]

@MerakiDave, when you have a moment, would you please look at the 3D Antenna Patterns that are attached and let me know if my orientation and signal pattern is correct. I modeled these with the AP/Antenna's pointing straight up and down. I would appreciate the advice.