Perhaps all of you know this already, but maybe for those who doesnt
My lilliput was interfering with my bu-303 gps. When i put on the lilliput i can see the signal is dropping with about 50%! (gps unit within a few feet of the lilliput). Because i dont have another good option for placing the gps unit somewhere else i started using aluminium foil.
It helped a LOT using aluminium foil behind the lilliput screen; almost the same signal strength when the lilliput is off. I also noticed you can get al LOT more signal strength when you put some aluminium foil under the gps unit, even when its on a metal underground already (for magnetic hold). The aluminium foil seems to reflect the signal and works like a sat-disc. Try it yourself and see the signal get better and better when you try to bent it a bit under it. I think the signal has got 50% better for me.