I was wondering if it’s good practice to setup the GNSS Multiband antenna with a metal ground plane or is it not necessary for this antenna?
Necessary vs Desirable?
It is generally desirable to use a ground plane to block signals from below the plane of the antenna. How large that is depends usually on practicality. A car roof is ideal, something 14-16″ in diameter is about the limit of any measurable benefit, 7-8″ in diameter is about the smallest I’d suggest.