The range cannot be considered independently from other requirements, because it relates to data throughput, local radio regulations etc. But in general the following factors ensure the best range:
-low RF frequency (provided the size of the antenna is sufficient)
-low data rate
-low RF channel bandwidth
-sensitivity of the receiver (which depend on the data rate and channel bandwidth)
-high RF transmission power
-antenna gain
Our 169MHz products will have the longest range. They reach several kilometers in practical appliactions. The mesh network technologies (Zigbee and Tinymesh) can also extend the coverage by using multiple hops to reach a node. Repeaters (Wireless M-Bus and KNX) and multi-hop (RC232) will also extend the range. The Sigfox technology is based on a cellular network to give city/country wide coverage. Check application note AN021 for further details here.

Last Update: December 2, 2019