Why are lower frequencies able to propagate further than higher frequencies?

Lower frequencies have the advantage of being able to diffract around obstacles more effectively because of their longer wavelengths. As the frequency decreases, the wavelength increases, allowing these waves to bend and curve around objects, such as buildings and hills. This property of diffraction enables lower frequency signals to maintain their strength and reach distances that higher frequencies might not, particularly in urban or rugged landscapes where such obstacles are common.

Higher frequencies, on the other hand, tend to be more line-of-sight and can easily be blocked by obstacles, leading to weaker signal strength and reduced propagation range. This is why lower frequencies are often preferred for long-distance communication and for applications where maintaining a reliable signal over various terrains is essential.

While it's true that lower frequencies may also experience less interference and can travel longer distances in some atmospheric conditions, the primary reason they propagate further is their superior ability to diffract around barriers.