Why is there no signal or signal interruption in the TV pot when it snows and rains?

If the signal of your satellite receiver is bad only because of the weather, then I can tell you the reason. It is because rain and snow in the sky will scatter and absorb the energy of radio waves, and the attenuation of rain and snow on radio waves will increase with the increase of frequency. Therefore, the rain and snow attenuation in Ku band is greater than that in C band. The reason why the signal in your small pot is bad when it rains and snows is now. However, you said that upgrading or replacing the motherboard can also solve the problem, so you can't rule out the reasons for satellite signal encryption. If your conditions permit, you can choose a bigger pot surface, which will be better. Or choose C band, the effect is better and the rain and snow attenuation is less.