Welcome @MaxTR,

Which device are you referring to?  The EAP110 Outdoor or the EAP225 Outdoor?  I know for the EAP225 Outdoor, the radio is a 2x2 design (two Tx chains and two Rx chains).  As such, for optimal speeds, one would prefer that the two antenna orientations be "cross-polarized" for signal diversity.

As such a "V" (like the Victory hand gesture from WWII or Live Long and Prosper from Star Trek) or "L" (one up, one horizontal) antenna orientation could potentially provide faster / more uniform speeds across the coverage area (for 2x2 STA's/clients) albeit with a slightly reduced coverage area.  I tried a number of antenna orientations for my EAP225 Outdoor.  I finally settled on the V-formation.  With the stock antennas I get about 100 feet of range on 5.8GHz with the AP mounted ~5 to 6 feet above the ground -- which covers my back yard nicely.

The other factor to consider is the proximity to the ground vs. the gain and orientation of the antennas.  The higher the antenna gain, the "flatter" the RF torroid (or donut" will be as it radiates out from a veritcal antenna.  With lower gain antennas (like is on the EAP225) the radiated RF signal is somewhat "rounder" / more "sperical" and if the AP is too close to the gound, some signal will be lost into the earth. 

One other detail, don't mount the outdoor EAP's upside down as they are not waterproof this way!

Best,

Jonathan

@JSchnee21 

Hi Jonathan

thank you so much for your explanations

the devices are 1 EAP110 Outdoor as Access-Point and 1 WBS210 as Client and one a foreign device (Delibrant)

the EAP110 was a replace after the WBS210 miss-worked as Access-Point (warranty)

in my case a horizontal radiation is necessary, the AP is mounted outside the building under the roof in maybe 6m (53 feet), the one Client and 3 IOT (ESP8366, Irrigation-System) are maybe 50 - 60cm (2-3 feet) over ground and one Client is mounted in 2m (7 feet) hight, distance are around of 20 - 25m (65 - 85 feet)

in case of free space under the roof, the AP device is horizontal mounted and therefor one antenna up and one down

so my thoughts about "cross-polarization" are mandatory or not, there is also a difference in general

the situation on site,

on the first Client (WBS210, LAN poe and LAN1) are connected an PLC and an Weather-Station,  on the second Client an further PLC (both Siemens LOGO!)

both PLCs  communicate with each other via the AP

the WBS210 had in this case the advantage because of the two connections, a switch was not needed

all is in the 2.4GHz band

I also will try now with other orientations of the antennas, for measuring the signal level I'm using inSSIDer from Metageek 

the other detail about upside down mode I know this not waterproof problem! 

thanks again, with kind regards

Max