You'll get a constant Signal Strength reading even with the Dish pointing at the ground - until you get close to a Satellite, the reading is only telling you you have an LNB connected and powered up. So I'm afraid you aren't getting a really strong signal - in fact, you have no signal at all!
Only when the indicated reading starts to change is that reading of use, and once the Quality reading kicks in, you optimise using that anyway.
I assume you are after UK Free To Air from Astra2/Eurobird?
First, have a look at Dishpointer to give you a good idea of where to point the dish - using a Compass is misleading and of no particular value.
Second, ensure that the Dish face seems nigh on vertical by eye: Although the required Elevation is around 25 degrees, the dish is an "offset" type where the LNB arm is at an angle of around 25 degrees already.
