The Texas Instruments CC1120 transceiver (ie “radio link” chip) is a small, very sensitive and quite “smart” device. We run it at 868MHz, which is a lower frequency than typical links like WiFi or most sensor networks (2.4GHz). This gives us the long range we need to link up areas of sensors which may be 1km apart. It uses little power – so conserves the batteries. TI make small test boards which are ideal for our research because making new RF boards is a complex/expensive process.