UHF M4 (9.5"x9.0") with Flat Screen Grid Reflector analyzed using 4nec2. Dimensions for Bowties are for mclapp's M4 using AWG8 per his website drawings. There was no attempt was made here (yet) to jointly optimize Bowtie & Reflector dimensions.
Two versions are presented, the first with a 32-in Reflector Width, the second with a 28-in Reflector Width. Modeling Results for a wide range of Widths is Charted below:
a) REFLECTOR = 40x32: Flattest Gain across all UHF Channels....and Good for Hi-VHF: 40-in x 32-in Screen Grid (1"x2") Reflector located 5.5-in behind 4-Bay Bowties.
UHF Raw Gain = 13.1 to 14.5 dBi, F/B & F/R Ratio Min = 20.1 dB and SWR (300-ohms) under 2.5. Hi-VHF Raw Gain = 8.6 to 8.9 dBi, F/B & F/R = 8 to 14 dB and SWR (300-ohms) = 3.9 to 12.7.
########################################################### b) REFLECTOR = 40x28: Slightly higher Gain on highest UHF Channels....but loses Gain, F/B & F/R Ratios on lower Hi-VHF channels: 40-in x 28-in Screen Grid (1"x2") Reflector located 5.5-in behind 4-Bay Bowties.
UHF Raw Gain = 12.8 to 14.7 dBi, F/B & F/R Ratio Min = 18.9 dB and SWR (300-ohms) under 2.5. Hi-VHF Raw Gain = 7.4 to 8.8 dBi, F/B & F/R = 2 to 10 and SWR (300-ohms) = 5 to 14.
ERRATA (27Oct2013): Corrected labels and narrative (charts remain the same). Separation between Reflector and Bowties is actually 5.5-in (vice 6.5-in). When defining the nec file names, I had overlooked -1 inch offset of Bowties.
Date(s): 27 Oct 2013. Album by holl_ands. 1 - 42 of 42 Total. 8689 Visits.
enlarge 113KB, 710x1024 1 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 32-in W Grid Size (1x2) 3D View
enlarge 307KB, 857x1024 2 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 32-in W Grid Size (1x2) Front View [1 large square = 5 inches]
enlarge 104KB, 341x1024 3 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 32-in W Grid Size (1x2) Top View [1 large square = 2.5 inches]
enlarge 182KB, 1152x686 4 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 32-in W Grid Size (1x2) UHF Raw Gain = 13.1 to 14.5 dBi UHF F/B & F/R Ratio Minimum = 20.1 dB
enlarge 208KB, 1152x686 5 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 32-in W Grid Size (1x2) UHF SWR (300-ohms) Under 2.5
enlarge 235KB, 1152x686 6 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 32-in W Grid Size (1x2) UHF Impedance
enlarge 303KB, 1024x1024 7 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 32-in W Grid Size (1x2) Azimuthal Pattern at 470 MHz
enlarge 302KB, 1024x1024 8 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 32-in W Grid Size (1x2) Azimuthal Pattern at 530 MHz
enlarge 301KB, 1024x1024 9 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 32-in W Grid Size (1x2) Azimuthal Pattern at 590 MHz
enlarge 302KB, 1024x1024 10 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 32-in W Grid Size (1x2) Azimuthal Pattern at 650 MHz
enlarge 304KB, 1024x1024 11 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 32-in W Grid Size (1x2) Azimuthal Pattern at 698 MHz
enlarge 304KB, 1024x1024 12 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 32-in W Grid Size (1x2) Azimuthal Pattern at 758 MHz
enlarge 304KB, 1024x1024 13 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 32-in W Grid Size (1x2) Azimuthal Pattern at 806 MHz
enlarge 130KB, 791x1024 14 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 32-in W Grid Size (1x2) 4nec2 File
enlarge 102KB, 401x1024 15 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 32-in W Grid Size (1x2) Side View [1 large square = 5 inches]
enlarge 179KB, 1152x686 16 M4 (9.5x9.0) 4-Bay + Grid Refl at 16-in 40-in H x 32-in W Grid Size (1x2) Hi-VHF Raw Gain = 8.6 to 8.9 dBi Hi-VHF F/B & F/R Ratio = 8 to 14 dB
enlarge 214KB, 1152x686 17 M4 (9.5x9.0) 4-Bay + Grid Refl at 16-in 40-in H x 32-in W Grid Size (1x2) Hi-VHF SWR (300-ohms) = 3.9 to 12.7
enlarge 245KB, 1152x686 18 M4 (9.5x9.0) 4-Bay + Grid Refl at 16-in 40-in H x 32-in W Grid Size (1x2) Hi-VHF Impedance
enlarge 305KB, 1024x1024 19 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 32-in W Grid Size (1x2) Azimuthal Pattern at 174 MHz
enlarge 305KB, 1024x1024 20 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 32-in W Grid Size (1x2) Azimuthal Pattern at 198 MHz
enlarge 308KB, 1024x1024 21 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 32-in W Grid Size (1x2) Azimuthal Pattern at 216 MHz
enlarge 119KB, 696x1024 22 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 28-in W Grid Size (1x2) 3D View
enlarge 262KB, 693x1024 23 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in Front View 40-in H x 28-in W Grid Size (1x2) [1 large square = 5 inches]
enlarge 112KB, 384x1024 24 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 28-in W Grid Size (1x2) Top View [1 large square = 2.5 inches]
enlarge 183KB, 1152x686 25 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 28-in W Grid Size (1x2) UHF Raw Gain = 12.8 to 14.7 dBi UHF F/B & F/R Ratio Minimum = 18.9 dB
enlarge 209KB, 1152x686 26 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 28-in W Grid Size (1x2) UHF SWR (300-ohms) Under 2.5
enlarge 237KB, 1152x686 27 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 28-in W Grid Size (1x2) UHF Impedance
enlarge 303KB, 1024x1024 28 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 28-in W Grid Size (1x2) Azimuthal Pattern at 470 MHz
enlarge 304KB, 1024x1024 29 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 28-in W Grid Size (1x2) Azimuthal Pattern at 530 MHz
enlarge 303KB, 1024x1024 30 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 28-in W Grid Size (1x2) Azimuthal Pattern at 590 MHz
enlarge 303KB, 1024x1024 31 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 28-in W Grid Size (1x2) Azimuthal Pattern at 650 MHz
enlarge 305KB, 1024x1024 32 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 28-in W Grid Size (1x2) Azimuthal Pattern at 698 MHz
enlarge 305KB, 1024x1024 33 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 28-in W Grid Size (1x2) Azimuthal Pattern at 758 MHz
enlarge 304KB, 1024x1024 34 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 28-in W Grid Size (1x2) Azimuthal Pattern at 806 MHz
enlarge 120KB, 791x1024 35 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 28-in W Grid Size (1x2) 4nec2 File
enlarge 97KB, 397x1024 36 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 28-in W Grid Size (1x2) Side View [1 large square = 5 inches]
enlarge 176KB, 1152x686 37 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 28-in W Grid Size (1x2) Hi-VHF Raw Gain = 7.4 to 8.6 dBi Hi-VHF F/B & F/R = 2 to 10 dB
enlarge 208KB, 1152x686 38 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 28-in W Grid Size (1x2) Hi-VHF SWR (300-ohms) = 5 to 14 Excessive, esp. on mid-high Channels
enlarge 242KB, 1152x686 39 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 28-in W Grid Size (1x2) Hi-VHF Impedance
enlarge 306KB, 1024x1024 40 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 28-in W Grid Size (1x2) Azimuthal Pattern at 174 MHz
enlarge 306KB, 1024x1024 41 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 28-in W Grid Size (1x2) Azimuthal Pattern at 198 MHz
enlarge 309KB, 1024x1024 42 M4 (9.5x9.0) 4-Bay + Grid Refl at 5.5-in 40-in H x 28-in W Grid Size (1x2) Azimuthal Pattern at 216 MHz
