Ron Hardin wrote:

I can report that dorms were fine for shortwave in 1960. I had a
KWM2 to communicate back home, even, my father and I being
K2DQA and K2DQB respectively. I had a 40m dipole hanging in the
trees.


Those must have been older dorms, or dorms in a different part of the
country (I'm in California). Most everything I've seen that's in current
use is concrete. Of course, if you string a wire up in a tree it's not
likely to matter, as I noted.