UHF+Hi-VHF HFF8, a Horizontal Stack of 2 ea Free-Form 4-Bays (FF4) with Double Angle Reflectors (DAR) (each 48" H x 36" W using 2x2-in Grid) and Holl_ands Horizontal Harness (HHH) were analyzed using 4nec2. Essentially all Dimensions were determined using nikiml's Python Optimization Scripts.
Performance was slightly "Better" at THREE notable Stacking Distances: 34.821-inches (NO GAP, Continuous Reflector), 35-inches (Metal-to-Metal about 1/4-inch) and 51-inches, which are analyzed below. There were notable Stacking Distances further out, but none were particularly "Better".
Although the differences are small, Stack Distance = 35-inches was just a bit "Better", esp. Hi-VHF, than at 51-inches, although the wider Separation may be slightly "Better" at combating Multipath Fading due to the reduction in Statistical Correlation between the two Antenna signals. The "NO GAP between Reflector" alternative was worse.
=========================================== a) Horizontal Stacking Distance (4-Bay Center-to-Center) = 34.821 inches (NO GAP between Reflectors).
T.B.D.
=========================================== b) Horizontal Stacking Distance (4-Bay Center-to-Center) = 35-inches (0.18-in GAP between Reflectors).
UHF Raw Gain = 16.9 to 20.1 to 19.8 dBi, F/B & F/R Ratio Min. = 15.7 dB and SWR (300-ohms) under 3.1. Hi-VHF Raw Gain = 14.3 to 9.6 dBi, F/B & F/R Ratio Min. = 8.5 dB and SWR (300-ohms) = 30.1 to 10.2 is Excessive.
=========================================== c) Horizontal Stacking Distance (4-Bay Center-to-Center) = 51-inches (16.18-in GAP between Reflectors).
UHF Raw Gain = 17.3 to 19.6 to 19.4 dBi, F/B & F/R Ratio Min. = 12.8 dB and SWR (300-ohms) is under 1.7. Hi-VHF Raw Gain = 10.6 to 9.7 to 11.6 dBi, F/B & F/R Min. = 12.6 dB and SWR (300-ohms) Min. = 10.4 is Excessive.
Date(s): 17 Oct 2014. Album by holl_ands. 1 - 42 of 42 Total. 3472 Visits.
enlarge 259KB, 887x1024 1 Horiz Stack 2xFF4 + DAR + HHH Stack Distance = 35 inches 3D View
enlarge 364KB, 1024x785 2 Horiz Stack 2xFF4 + DAR + HHH Stack Distance = 35 inches with Small Gap between Reflectors Front View [1 large square = 5 inches]
enlarge 111KB, 313x1024 3 Horiz Stack 2xFF4 + DAR + HHH Stack Distance = 35 inches with Small Gap between Reflectors Top View [1 large square = 5 inches]
enlarge 164KB, 1024x690 4 Horiz Stack 2xFF4 + DAR + HHH Stack Distance = 35 inches UHF Raw Gain = 16.9 to 20.1 to 19.8 dBi UHF F/B & F/R Ratio Minimum = 15.7 dB
enlarge 126KB, 415x1024 15 Horiz Stack 2xFF4 + DAR + HHH Stack Distance = 35 inches with Small Gap between Reflectors Side View [1 large square = 5 inches]
enlarge 167KB, 1024x690 16 Horiz Stack 2xFF4 + DAR + HHH Stack Distance = 35 inches Hi-VHF Raw Gain = 14.3 to 9.6 dBi Hi-VHF F/B & F/R Minimum = 8.5 dB
enlarge 198KB, 1024x690 17 Horiz Stack 2xFF4 + DAR + HHH Stack Distance = 35 inches Hi-VHF SWR (300-ohms) = 30.1 to 10.2 is Excessive
Great antenna design! Question, would a sing FF4 have similar specs less about 2.5dB across the board? I can't fit this model in my location but a single would work well and far exceed the specs of a GH I built.
