Yes sure, the antenna works in the same way bidirectionally.
But bidirectional transmission is done in different ways:
- when the node receive the transmitter antenna is big and efficient.
- when the node transmit it is not grant that the more efficient receiver antenna can compensate the poor node antenna gain.
The battery should be not a problem because the power is limited by regulator.
ERC Recommendation 70-03
g 863.0 - 868.0 MHz 1% or LBT+AFA, 25 mW (=14dBm)
g1 868.0 - 868.6 MHz 1% or LBT+AFA, 25 mW
g2 868.7 - 869.2 MHz 0.1% or LBT+AFA, 25 mW
g3 869.4 - 869.65 MHz 10% or LBT+AFA, 500 mW (=27dBm)
g4 869.7 - 870.0 MHz 1% or LBT+AFA, 25 mW (no dutcy-cyle requirement if power < 5 mW/7 dBm)