Does the rain affect the satellite signal?

You have just turned up at your favourite camping site in France. Set up your satellite dish on the tripod, aligned it and everything is working fine. The Sky box indicates you are getting both signal strength and quality. Then it starts to rain!
When you switch the TV on, there is a message reading “No Satellite Signal” on BBC 1. Most of the other channels are working fine and you are wondering why it has suddenly stopped working on BBC 1. Does the rain have any effect on the satellite signal?

The answer is yes, the rain does affect both satellite signal strength and quality. As you move further away from the UK the satellite signals for the UK become weaker and more prone to breaking up. This is the reason you need a larger satellite dish. The Astra 2D satellite that carries the BBC, ITV & CH4 transmissions is weaker than the other satellites and is usually the first signal to be lost.

The satellite signal is affected in 3 ways by rain.

  • An increase in attenuation of the satellite signal due to scattering and absorption.
  • An increase in noise power (interference), due to the rain drops being considerably warmer than the back ground temperature of space.
  • Depolarisation causing co-channel interference from the opposite polarity.

Correct dish alignment and LNB skew will often help remedy poor satellite signal strength & quality. But if the satellite dish is too small for where you are located there is not much you can do but increase the satellite dish size.