For radio waves of the VHF band and above, what reduces the effective range and quality of transmission?

The effective range and quality of VHF band radio transmissions are significantly influenced by environmental factors. Atmospheric absorption is a key factor that affects higher frequency signals. When radio waves encounter atmospheric gases and moisture, energy can be absorbed, thus reducing the strength of the signal as it propagates. This is particularly relevant to frequencies in the VHF range and above where absorption becomes prominent due to the molecular composition of the atmosphere.

Additionally, tropospheric conditions, such as humidity, temperature gradients, and scattering, can further impact the clarity and distance over which VHF signals can effectively transmit. These conditions can cause variations in refractive indexes, leading to a phenomenon called "multipath propagation," which can distort the received signal quality.

By considering these aspects, it is clear that atmospheric absorption directly diminishes the signal strength over distance while tropospheric conditions can create variations that complicate effective transmission further. This makes the identified answer well-suited to explaining the factors that reduce the effective range and quality of transmission in the VHF band and above.