https://en.m.wikipedia.org/wiki/Radio_propagation https://en.m.wikipedia.org/wiki/Radio_propagation covers it a little bit. The short answer is that wavelength(

https://en.m.wikipedia.org/wiki/Radio_propagation https://en.m.wikipedia.org/wiki/Radio_propagation covers it a little bit. The short answer is that wavelength(aka frequency) vs raindrop size causes signals to scatter instead of attenuate and you can pick up a fraction of the original signal.