I built a version of the original GH w/ all 7" elements (#8 solid Cu wire) + Tophats ( 6.7" center ,3.5" @ 45 degrees , 8.15" Tails for a total length of 30") . I retrofitted this build in front of a 36" x 20" Grid Screen (1" x 2" ) from an old 4-Bay Bowtie similar to CM4221 . The tophats are in the same plane as the Zig-Zag elements which are 4.5" in front of the screen. The goal of this build is a backup indoor antenna facing south on second floor , for real RF channels 24 ,26 ,36 , + VHF 10 . Reception of the UHF is great w/ RCA U-V amp , signals rated @ -76dBm per tvfool , 2 edge . Channel 10 is marginal @ screen facing south .
My outdoor main antenna is a CM 4228a w/ Winegard LNA200 pointed at 116 degrees for the rest of my stations.
My question : Your History folder shows grid screens of 36" x 40" , Split and solid . Do you have any NEC2 analysis available for a geometry similar to mine , or these old designs ? I am curious how much net gain I am not getting . When I eventually place my new build GH outside , I would like best performance on all UHF 15 through 36 + VHF 8 and 10. That new build will likely be GH4n3 when I can tolerate reflectors 50" in total width . Can you publish any of the NEC2 analysis and geometry from your older GH antennas in front of a Grid ?
About me : Retired RF Engineer; first Yagi build in 1973 ! No RFtest equipment , or Analysis Software , yet.