Which of the following frequency bands would most likely provide reliable communications between two stations that are 100 miles (160 km) apart?

The reason the Medium Frequency (MF) band is the most suitable choice for reliable communications over a distance of 100 miles (160 km) lies in its propagation characteristics. MF frequencies, which typically range from 300 kHz to 3 MHz, have the ability to follow the curvature of the Earth due to their ground wave propagation properties. This allows for effective communication over considerable distances under standard conditions.

In contrast, while the Very High Frequency (VHF) band can offer clear communication over shorter distances and is favored for line-of-sight applications, it may not be reliable for distances as great as 100 miles because VHF signals do not typically bend around the Earth and are affected significantly by obstacles such as buildings and terrain.

The High Frequency (HF) band has excellent long-distance propagation capabilities due to its ability to reflect off the ionosphere, which can allow for communication over thousands of miles. However, HF may not be as consistent for relatively short distances like 100 miles, especially during certain times of day or under varying atmospheric conditions.

The Low Frequency (LF) band is primarily used for navigation and specific types of broadcasting but generally does not support effective communication over such distances compared to MF, as its propagation properties tend to be less efficient for