You are selecting external antennas for use in a bridge link deployment.

Comprehensive and Detailed Explanation:

An elevation chart provides a vertical radiation pattern of an antenna, which is essential for understanding how the antenna directs energy above and below the horizon. In bridge link deployments, especially over varying terrains or between buildings of different heights, the elevation pattern helps in aligning antennas to ensure optimal signal propagation and reception. Requesting elevation charts from antenna vendors allows for informed decisions on antenna placement and orientation, leading to more reliable and efficient wireless links.