Wireless Access

Hello everyone im trying to understand clearly this... today i was reading one VRD completely of Design

The thing is that i think i got it but still im asking to be 100%

When you got an internal AP with downtilt Antena like ap 135 or ap 105 and you put it on the ceiling you need or have to be careful in how high is the ceiling, because depending how high is it,  the circle  is bigger so the coverage in a room would be better...

As for as far i read downtilt antenas is like a mix of omnidirectional and directional antena.

Now if the celing is not that high, then i should pick a AP 125 which it as far i see on the radiation pattern on the E plane looks more like a donut so it would be good for that case.

Now my question is

1-I am right ? or did i misunderstood something

2-How high should be de celing so i can place ap 105 and ap 135? it does not need to be like reallly accurate something to guide me.

If its like this it would be a good idea if you guys could do ap 125 2x2:2 instead of 3x3:3 so it can be cheaper :)

Any other comment or extra comment about this topic is welcome :)

1. Yes, you are right.

2. When mounted at typical (office) ceiling height, the horizontal gain of these downtilt omnis may indeed be slightly lower than traditional omni dipoles (as used by AP-125, or when using external "stick" antennas with an AP-134 or AP-104), but given the indoor environment (i.e. not open space, with lots of reflecting surfaces and attenuating objects) this is typically not noticeable. When mounted on a high ceiling (warehouse for example, can be 20ft or more), the downtilt (cone) pattern actually has a big advantage compared to the traditional donut shaped gain pattern of an omni.