After reading this thread I suspect my LNB may also be on the fritz. I'm suffering similar symptoms, Freeivew/DVB-S reception has gone downhill with the recent fine weather.

Some background:

I've recently re-run RG-6 directly from the satellite to the receiver and terminated both ends with compression fittings so am fairly confident the cable isn't the issue. The dish itself is an old Sky one and has definitely seen better days. We got Sky 24 installed months ago and the technician replace the LNB on an old dish that was installed by the previous owners. We since canceled Sky after 12 months. The dish has the usual weathering etc but doesn't appear to be damaged on out of shape etc. I believe the new LNB is the usual Sharp quad LNB installed by Sky.

Are there any merits to replacing the dish? or would replacing the LNB be sufficient?

Any tips or pointers on a quality brand of LNB that wont crap out like the Sharp's?