I'm wondering about the best materials for making a ground plane. I've found some websites that claim that non-ferrous materials (i.e. aluminum) are generally poor ground planes (or at least not as good as the same size of a ferrous ground plane). Other sources claim this is a myth.
Does having a ferrous material for a ground plane matter? If so, why does it matter?
Both your provided links sound like they were written by someone with very little understanding of how antennas work. I would ignore them entirely.
A ground plane is a necessary part of a monopole antenna, often called a "vertical" since that's how they are usually mounted. These antennas are essentially half a dipole, with the other half being the electrical "mirror" of the antenna on the other side of the ground plane.
The only requirement for the ground plane is that it conducts. The more conductive it is, the better. The bigger it is, the better. Professional AM radio broadcast antennas use lengths of copper wires buried just under the ground, radiating out from the base of the antenna, to make the Earth more like an ideal ground plane. I'm sure if iron worked better, they'd use iron, as it's much cheaper than copper.
If I had to guess, the reason CB operators think ferrous metals make better ground planes are two-fold:
If you don't actually have an antenna, then none of this applies. The lesson to be learned is this:
Don't use references written by CB operators as a source for learning about electrical engineering of any sort.
