UHF+Hi-VHF Vertically Stacked 2x FF6 (Free-Form 6-Bay Bowties) with Variable Double Angled Screen Grid Reflector (VDAR) analyzed using 4nec2 after finding BEST Dimensions using nikiml's Python Optimization Scripts. HVH (Holl_ands Vertical Harness) Interconnects two FF6's.
Screen Reflector (60" H x 36" W Unfolded) using 2x2-in Grid was assumed in fol. model to remain within operating (and time) constraints. If 2x1-in Grid is used, F/B & F/R Ratios would be much higher.
UHF Raw Gain = 18.2 to 20.6 to 20.3 dBi, F/B & F/R Ratio Min. = 13.0 dB and SWR (300-ohms) Under 2.3. Hi-VHF Raw Gain = -4.1 to 13.0 to 12.4 dBi, F/B & F/R Min. = 17 dB Except Much Lower on Ch7+8 and SWR (300-ohms) is Excessive.
Note that UHF Elevation Beamwidth is only 5-3 degrees (and 10-deg for Hi-VHF), which requires the user to KNOW the expected Angle of Arrival and mount the Antenna with sufficient LOOK UP ANGLE (or in rare cases LOOK DOWN ANGLE).
Date(s): 2 Jan 2016. Album by holl_ands. 1 - 35 of 35 Total. 2419 Visits.
enlarge 119KB, 487x1024 1 Vert-Stack FF6 + DoubleAngleRefl. 3D View
enlarge 188KB, 421x1024 2 Vert-Stack FF6 + DoubleAngleRefl. Front View [1 large square = 12.5-inches]
enlarge 125KB, 342x1024 3 Vert-Stack FF6 + DoubleAngleRefl. Top View [1 large square = 2.5-inches]
enlarge 174KB, 1024x794 4 Vert-Stack FF6 + DoubleAngleRefl. UHF Raw Gain = 18.2 to 20.6 to 20.3 dBi UHF F/B & F/R Ratio Minimum = 13.0 dB
enlarge 176KB, 1024x794 19 Vert-Stack FF6 + DoubleAngleRefl. Hi-VHF Raw Gain = -4.1 to 13.0 to 12.4 dBi Hi-VHF F/B & F/R Minimum = 17 dB Except Much Lower on Ch7+8
