Hello Nicola
Great Spot, and really good idea to use a fence or a ramp as a ground. With this, no need to install radials on the ground.
And if we look around, when we go portable, there are plenty of place with some "GUARDS" like the one on the photos, or some métal fence.
Here at home I use my "chain link fence" around my lot, at the back of the house as a ground counterpoise for my verticals antennas made of Buddipole/Buddistick parts.
My fence has: 154 foot long or 55 meters long.
I use a special home made Bracket to hold my vertical, and a balun. I have another one for portable operation, just in case , if I find an opportunity to use it to some metal guard.
Always "FULL SIZE/NO COMPROMISE"
Congrats Nicola, Great and sure fun installation, you certainly had good results with this.
72, Michel VE2TH\ Back to the QRP.. didit...