Outdoor antenna conductors must not be smaller than __________ copper where the maximum open span length is 45 ft.

The correct answer, which specifies the appropriate size for outdoor antenna conductors, reflects the standards set for ensuring safety and performance in electrical installations. In this case, the requirement states that with a maximum open span length of 45 feet, the conductors used must not be smaller than 17 AWG copper.

Using conductors of this gauge ensures that the antenna can properly handle the electrical loads it experiences, reducing the risk of overheating and failure. The size of the conductor is crucial as it affects the resistance, and hence the efficiency of the antenna system. A 17 AWG conductor strikes a balance between being sufficiently robust to handle the demands of the installation while also maintaining flexibility and ease of handling.

In contrast, options reflecting smaller gauges, such as 18 AWG or 16 AWG, would not meet the necessary conductivity and load-bearing requirements for this specific application, making them inappropriate for deployments with spans of this length. Similarly, even though 14 AWG is larger and could technically handle the load, it would exceed the minimum size stipulated, which is specifically defined as 17 AWG under these circumstances. Thus, the standard reflects careful consideration of both safety and performance in antenna systems.