Upon further review, and voiding of the warranty (ducks), took one glance to find the issue which was confirmed to be a broken antenna connection. Looks like it may have been a fragile cold joint. It also wasn't sitting straight in the case. I'm guessing UPS's routine handling procedures resembling those of Stephen Gostkowski during the 2017-2018 regular NFL season probably are what did it in, despite Uniden's retail packaging. Retailer also didn't throw any peanuts or air-packets in the shipping box.
After a quick fix with the soldering iron, and closing it back up, the SDS100 is now out performing every other scanner the four of us have spread on the table, except our buddy's Unication G5 on WVSIRN where it's about equal. Hopefully it's equally as good on NJICS when we get back to Jersey on Monday.
I'm actually also really damned impressed with conventional reception in the AAR Band attached to the full-size Stationmaster up on the pole outside the cabin.