The transmit power of the radio determines how far it reaches. The TX power can be configured, but note that there might be rules and regulations in different countries that limits which settings that are allowed.
How to configure
The configuration of the anchors determines the TX power of the anchors, if you are using the TWR mode you also have to configure the TX power of the Loco deck on the Crazyflie to increase the system range.
The anchors must be configured with the power mode: ForceTxPower and the desired power level (9 is highest),
see the low level configuration section
The key sequence to use in the configuration is:
p- the power menuf- forForceTxPower- a number key for the desired power level
Remember to reboot the node for the changes to be active.