Mt. Wilson, Cal. Major disadvantage is poor resolving ability. Wavelengths of radio waves are 1000's of times larger than those of visible light. Use arrays of 2 or more to increase resolution. May be miles apart.
Atmosphere introduces distortions - stars twinkle.
Patches of warm air bend light rays. Dust, clouds, and humidity diminish light intensity. Lights on the ground interfere with observations. Earth's gravtational field distorts large mirrors and lenses, and limits precision of pointing of large instruments. Earth is rotating, limiting what you can see and length of observations.