Thanks everyone for your help and timely responses! I was pretty sure that the signal booster switch was behind the TV. We are sharing our 320RS with my in-laws who have been using it this week. My father-in-law said that he could not get a good picture from the cable signal and was just using the antenna. I knew this must be from the booster switch, since with our previous unit the cable signal was fuzzy when the switch was on. Now I can be the genius and tell him how to fix it.
I guess the excitement of getting the new unit fogged my judgment a bit, since I didn't pin down the RV Tech with a complete answer.