Why is there a grid below the antennas of an VOR? A few days ago I made a trip to the VOR-DME near my local airport LOWG, because I always wanted to see one. It's GRZ on 116.2.

When I was there, I wondered why there is a giant metal grid under the actual antennas of the VOR.



Source: Klaus Krasser

Close picture:



Source: Klaus Krasser

The grids squares have a size of estimated 10x10 centimeters.

What is this grid for? Is it maybe used as a shield or reflector? 116.2 Mhz has a wavelength of ~2.6 meters, so the grid would reflect the radiation. If thats the use of the grid, why is it needed?
I think this is an example of a counterpoise:


  [It] is a network of suspended horizontal wires or cables (or a metal screen), used as a substitute for an earth (ground) connection in a radio antenna system (...) when a normal earth ground cannot be used because of high soil resistance or when an antenna is mounted above ground level.


Generally used for LF and VLF antennas as that is where they are most efficient.

An example from that Wikipedia page of an AM radio antenna counterpoise: