Saw this come across on the wire and thought I just have to comment about this. Have no idea what the implementation team was thinking of..I call this as well "interesting".
- The AP is sending RF energy up through a metal frame,(plate) (has to because concrete below) then the metal seat,(which is like a Farady cage) then through a human body.(high absorption). Reflectivity and attenuation goes through the roof.
- Flex cable looks like plastic conduit for POE (Power over Ethernet) to powered AP, sitting under a seat of patron. Looks like a real safety issue to me.
- Next the Near field issue. So now I have my I-Pad, or other and on the WLAN, but I am less than a foot from the AP.
- EIRP. (Effective Isotropic Radiated Power) Not quite sure the type of antenna that they are using, but this set up seems to look like a real "hot seat".
Why not mount the AP(s) across the ceiling of the stadium and use custom directional or a YAGI that directs RF over the club seating that can provide isolation from the other wireless systems on the field?
A Yagi-Uda array is a directional antenna consisting of a driven element (typically a dipole or folded dipole) and additional parasitic elements (usually a so-called reflector and one or more directors). The reflector element is slightly longer (typically 5% longer) than the driven dipole, whereas the so-called directors are a little shorter. This design achieves a very substantial increase in the antenna's directionality and gain compared to a simple dipole.
Effective Isotropic Radiated Power (EIRP) is the output power when a signal is concentrated into a smaller area by the Antenna.
An isotropic radiator radiates power equally in all directions, however a perfect isotropic radiator is only theoretical as even the simplest antennas will concentrate the signal in certain direction(s). E.g. a 1/2 wave dipole has a gain of 2.15 dBi.
When installing a wireless system with external antenna, your EIRP calculation should not exceed the class license limit. Other wise you must adjust either the transmitter power output, the length of cable and/or the choice of antenna.
