The coupler to emphase antennas features an amplification stage.
However, the signals received do not need amplification.
Can this active coupler work without a powering voltage since amplification is not necessary?
No. A piece of active equipment needs to be powered to work, even if more gain is not needed.
If passive coupling is needed, we recommend our diplexer ref. 4004, and remember to load the VHF port if not used.