This device is a Wifi access point and should provide a stable radio coverage of your arena.
When mounted at a height of 3 m this Radio Base provides 25-30 meters diameter of the signal coverage area. So the square of confident signal reception from one device is 300-400 square meters.
The dimensions of the device: 80x50x28 mm
Power supply: 4.5 … 15 volts
Communication: 10/100 Mbit LAN.