Perhaps Intrac meant the white circular cover in the front, as opposed the the gray plastic housing?
If that is the case, I seem to remember that someone suggested using a plastic lid from an aerosol can as a replacement to keep moisture and rain from collecting inside.
Keeps the 'dobbers from setting up housekeeping on your dipole. That'll sure wreck a polarotor assy.................also be sure to make a few small icepick size punctures at the bottom to allow it to 'breathe' and condensate to escape. Talk about an intermittent signal issue that will drive you buggy. Works fine in the middle of the day but goes whack at night coincidently when the night temp reaches DEWPOINT....go figure.
I'm curious Smitty, who's he to PM? He said he could not find the original thread.
I think it's just necessary if you need the clamp throat to be a certain size or if you want to be extra sure to keep water out of the electronics (instead of relying on the seal from the LNB body and the thin metal electronics cover to be done correctly at the factory).
I think it looks cooler naked (and smaller clamp area, too - with the plastic gone, meaning I can use some of my older smaller clamps to hold it and don't need the 1.5 inch or so clamps).
This aint the other areas of satguys. This is the FTA area where we have more lax rules (and more fun) 
