How can radio waves behave in urban canyons?

Radio waves behave in urban canyons primarily by experiencing multipath propagation due to reflections. In densely built urban environments, buildings and other structures can reflect radio waves, creating multiple paths for the signals to reach a receiver. This means that a single transmitted signal can arrive at the receiving antenna via different routes, having been reflected off various surfaces.

This multipath effect can lead to constructive or destructive interference, where the overlapping signals can either combine to strengthen the overall signal or cancel each other out, resulting in fluctuating signal quality. This behavior is particularly significant in urban areas where the landscape is filled with tall buildings that can act as reflective surfaces.

The other options do not accurately describe how radio waves behave in these environments. For instance, radio waves do not travel in perfectly straight lines in urban canyons due to the presence of obstructions that create reflections. While some absorption might occur, especially at higher frequencies, it is not complete and does not characterize the primary behavior of radio waves in such settings. Similarly, while propagation can be affected, it does not mean that radio waves fail to propagate effectively; rather, the complexity of the urban landscape influences the signal characteristics significantly.