So I could not get the 3890 mux on 97W. Today was quite warm for some reason so I decided to try to peak my 12 foot Unimesh. Swung the dish over to AMC 8 and got the ladder out. Decided to remove the cap on my ortho feed to check for bugs first. Pulled it off and as soon as I saw it I remembered hunting some circular stuff over the Atlantic a year or so ago. I had glued a dielectric plate to the cap and forgot about it. Oh well signal is back to normal across the board now and we will write this off as a senior moment, or in this case a year and a half!