The problem might not be as much of an LNB problem as it is a NOISE problem. While a better quality LNB can help by reducing overall system noise, the fact that the dish is pointing at such a low look angle will introduce much more earth noise. North American customers who have contracts using this satellite will generally use a much bigger dish so that the tighter beamwidth will help reduce the amount of earth noise received.
This effect can be simulated by connecting a dish to a receiver and observing the signal meter while not pointed at a satellite. Note the signal when the dish is pointed skyward into clean air, then lower the dish toward a group of trees or a building and watch the signal rise.