Antenna ground plane

[mafiltenborg]

In an attempt to get the most out of the tiny antennas that came with my Heltec V3 devices (868MHz), I'm wondering if it would help to install them on a 'ground plane'.
You know, a bit of steel plate extending at least 1/4 wavelength to all sides of the antenna screw-mount-socket. In my case 9cm or more; a 20cm diameter disc with a 6.5mm hole in the center.

Anyone who's done experiments with that?