"DC" wrote:
"Basically I have been told that shorter wavelength waves attenuate and
scatter more easily."

That is only part of the story. To pass through an opening, the wave
must be small with respevct to the opening to avoid severe attenuation.
An example may be evident when you are tuned to an AM broadcast on a car
radio and you enter a bridge, tunnel, or parking garage. The AM signal
may disappear. If you tun-in an FM signal, it may be strong. The FM
wavelength fits through pores in the structure.

In a tunnel, the diameter must be at least 1/2-wavelength not to
severely attenuate attempted propagation of a wave through the tunnel.

Best regards, Richard Harrison, KB5WZI