Why might a technician be asked to measure signal levels on the highest and lowest downstream channels?

The most appropriate reason for a technician to measure signal levels on the highest and lowest downstream channels is to assess overall network performance. Measuring signal levels across the entire range of channels helps ensure that both the highest and lowest frequencies are functioning correctly. This process provides a comprehensive view of the network's health, allowing technicians to identify any potential issues related to signal degradation or interference that might occur at different channel frequencies.

In particular, monitoring these extremes can reveal variations in signal quality due to factors like line loss, noise, or interference that may not be evident if only middle channels were tested. By obtaining this data, technicians can make informed decisions about maintenance or upgrades needed to optimize the network’s performance.