Nice ZWave far away Homey


I have a nice portal and i bought the FG-IBT4ZWAVE device.
The distance between my portal and my Homey is about 50 meters and it doesn’t ok because the distance.
The device’s internal antenna is 10dbM but i don’t know really which distance it works.
I can add a plus to extend my zwave mesh but the plug is far away 40 meters the portal.
I can also add an antenna to the device ta add 3dbi more.
I don’t know how i can do.

Thanks a lot