Happy to report that it's an antenna height issue!? I went to the site of the gateway, transmitted at 5W, and it worked flawlessly.? Backed it up 5 miles, then 10, and kept increasing power.? Finally lost connection a few miles from my home (total distance is 17 miles).? So, I either will get a VHF radio amplifier (pricey for 160W!); or ask HOA if I can somehow put an antenna on the roof. ?:)
Jason, THANK YOU for all of your help these past several months!