When you say fuzzy, do my you mean like a "snowy" analog signal? If so, that would not be your equipment. It's most likely D*'s SD feed from the local station. Sometimes they have to use OTA to get the channel and there could be interference or equipment problems cause them to get a poor signal.
By the way, you say it's not this way on your HD receivers. Are you getting this channel in HD from D*? If so, try tuning one of the HD receivers to the SD version of the local and see how it looks (you may have to unhide SD duplicates in the menu). If the SD version of the local is snowy/blurry on your HD receiver, then my theory is probably correct.