What is an essential safety practice while working at height on antenna towers?

Wearing a reflective vest is crucial for safety while working at height on antenna towers because it enhances visibility. When working in elevated positions, there may be other people or vehicles in the vicinity, and a reflective vest helps ensure that individuals are easily seen, reducing the risk of accidents. Visibility is essential in any work environment, especially in situations where workers may be at risk from moving equipment or other workers who may not be aware of their presence.

The other choices do not directly contribute to immediate personal safety while working at heights. For example, while using multiple power sources or a radio could be part of a safety plan, they do not specifically address visibility. Refraining from using tools is impractical, as tools are necessary for the work being performed on the towers. Thus, wearing a reflective vest stands out as an essential safety measure in this context.