Long-range communications are used at which part of the spectrum?

Long-range communications are used at which part of the spectrum?

• A. Lower end of spectrum
• B. Higher end of spectrum
• C. Midband
• D. Wideband

Answer: (A)

Lower-frequency signals travel farther because their longer wavelengths diffract around obstacles and can reflect off the ionosphere, enabling skywave propagation that covers vast distances beyond the horizon. This makes the lower end of the spectrum ideal for long-range communications. Higher frequencies tend to be more line-of-sight and suffer greater distance-related loss, limiting their reach. Midband is just a central frequency range, and wideband refers to how much bandwidth a signal has, not how far it can travel. So the best fit for long-range use is the lower end of the spectrum.

Lower-frequency signals travel farther because their longer wavelengths diffract around obstacles and can reflect off the ionosphere, enabling skywave propagation that covers vast distances beyond the horizon. This makes the lower end of the spectrum ideal for long-range communications. Higher frequencies tend to be more line-of-sight and suffer greater distance-related loss, limiting their reach. Midband is just a central frequency range, and wideband refers to how much bandwidth a signal has, not how far it can travel. So the best fit for long-range use is the lower end of the spectrum.