Stacking antennas to improve performance is nothing new.
I installed stacked antennas in weak signal areas for over 2 decades. In the beginning I had to experiment to find the best combination of antennas and find the proper spacing distance between the antennas. Once I found the perfect set up I installed the same antennas over and over with great success. Back then I called it the "Bi-Powered antenna".
Do to the success of our on line antenna business I retired from antenna installation service in 2008 and my son Tony started Tony D's antenna service here in Michigan. At the time the Country was switching from analog to the new digital signals. We soon found out people living in weaker signal areas needed a very large antenna to consistently receive the new digital signal. Our most popular antenna at the time for us and maybe every dealer was 110" wide and 131" long.
I thought to myself. There's got to be a better way. Why not design a stacked antenna system. Design it so the two antennas compliment each other. So I started grabbing various antennas from around the shop and began cutting and spacing antenna parts. After a couple of months of design work in my shop I was satisfied I had an antenna I could present to Winegard. My goal was to create an antenna that is no longer than 72" without forfeiting the performance provided by the 131" antenna.