Broadband Fixed-Access Network Hardware Evolution

Over the past 5 years, spectrum has been allocated on a country-by-country basis at 3.5
GHz, 10 GHz, 26 GHz, 28 GHz, 38 GHz, 39 GHz, and 40 GHz for broadband fixed
wireless access. Available bandwidth increases as frequency increases, but propagation
becomes more unpredictable. Over 10 GHz, communication effectively has to be line of
site.
The link budget also becomes very dependent on climatic conditions. As you move
into the millimeter bands (30 GHz to 300 GHz), the wavelength is the same length as a
raindrop (or a hydrometeor to use the correct description). Raindrops in effect scatter
the radio waves. This is known as nonresonant absorption.