I have a 90cm dish with 1x C band LNB and 2x Ku band LNBs mounted on it, I got the channels I require, no problem with that.
The problem is that the channels on the LNB with the most offset (as expected) get really bad early in the morning(05:00 - 08:00), when I try to watch / record (standalone DVB-S receiver / DVD HDD recorder). If the Sun goes up, the reception improves a lot (signal goes from 25% up to 70 - 75%). This does not happen in the warm mornings, only in the cold mornings, when there is lots of due everywhere (including on the dish). If it is raining, it is working fine (even if the signal is weaker, is perfectly stable and watchable).
I believe it is something to do with the way the water from the rain wets the dish surface (a continuous film - more or less) as opposed to the way the due forms - here and there, dripping down here and there, which makes the surface reflecting the signal to go quite away from the steel shape (due to all the droplets sitting on the dish, I believe).
I am thinking to try and apply a water repellant coating onto the dish surface (silicone / CRC / oil spray?)- could this interfere in any way with the dish characteristics? I do not see any downside, but other people out there with more indepth knowledge of how the signal propagates / reflects might have an opinion?
I am also thinking: if the coating remains sticky then possibly leaves, feathers or even dust will adhere to the surface then possibly making things even worse (and more permanent)? It sounds ridiculous, but did anyone ever saw a dish with a little roof / awning on top to protect against due formation?
(I also thought of using some of the electric underfloor heating cable applied to the back of the dish and controlled by a timer but this is way over the top... ha... ha...).
Any thoughts will be much appreciated.