What term describes the action of beam outdoor microwaves blocking signals?

The term that accurately describes the action of beam outdoor microwaves blocking signals is "obscuration." This term refers to the phenomenon where a signal is partially or completely obstructed by an object or condition, leading to a failure in signal transmission. In this context, when microwaves are transmitted outdoors, they may be blocked by physical barriers or other influences in the environment, resulting in a diminished or nonexistent signal.

In contrast, interference refers to the alteration or disruption of signals due to overlapping frequencies or external sources, but it does not specifically involve blocking. Refraction is the bending of waves as they pass through different mediums, which can alter the path of a signal but does not directly imply that it is being blocked. Dissipation relates to the loss of energy of a signal as it travels, rather than a physical blockage. Therefore, obscuration best fits the concept of signals being blocked by outdoor microwave beams.