I've been flying into Pittsburgh's Allegheny County Airport once a month or so for the past couple of years. I've always had trouble flying the ILS there and long ago started requesting the RNAV. However, a couple of days ago I flew it in VFR conditions and could clearly see the needles going all over the place. There average position seemed to roughly correspond with the approach but with a very high 'noise level'. Not really flyable. I then flew an ILS elsewhere and found the needles accurate and steady as always. I'm thinking some unholy combination of my installation and the gnarly hill top location of the transmitter is the culprit. Anyone else experience this at KAGC?