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holl_ands | Home > Bowties, Dipoles, Batwings & Rhombics > Browse:UHF Stick Dipole - No ReflectorUHF Bowties - NO ReflectorUHF Fractal Bowtie - No ReflectorUHF CM4248 Folded Dipole Bowtie (ONLY)91XG Dipole ONLY & Dipole+First DirectorUHF Batwing - No Refl & Screen Grid ReflUHF Small Rhombic StackUHF Double RhomboidVHF Stick Dipoles incl Horiz.Rabbit-EarsHi-VHF+UHF Stick Dipole - No ReflectorHi-VHF+UHF "VEE" Stick DipoleHi-VHF Bowties - No ReflectorLo+Hi-VHF 1-Bay Bowtie - No Reflector
UHF Fractal Bowtie - No Reflector UHF 4th Order Sierpinski Arrowhead (Fractal) Bowtie analyzed using 4nec2. Three feedpoint geometries were analyzed: 1) End-Fed Anti-Symmetric (mirrored on Centerpoint vice Z-Axis) provided best Raw Gain and SWR, but SWR was excessive on the lower frequencies, limiting the useful bandwidth. The sharp dive in the (Forward) Gain curve corresponds to when the Azimuthal Pattern changes into a four-leaf clover, with minimal Forward Gain...also note that Real Part of Impedance, R(ohm), nose dives down to only 25-ohms, resulting in a very high SWR peak.  These severely limit the usable bandwidth. 2) End-Fed Symmetric (mirrored on Z-Axis) had poor Raw Gain and SWR identical to End-Fed Anti-Symetric. 3) Center-Fed Symmetric had poor Raw Gain as well as poor SWR. These antennas would need to be Rescaled to match the desired operating band since they were very poor matches for existing UHF Band.  SOURCE Wire length should them be varied to obtain best SWR. Date(s): 21 Jan 2013. Album by holl_ands. 1 - 18 of 18 Total. 11392 Visits.
enlarge 66KB, 1024x1004 1 End-Fed Anti-Symmetric Fractal Bowtie 3D View enlarge 335KB, 1024x1004 2 End-Fed Anti-Symmetric Fractal Bowtie Front View [1 big box = 1.25 inches] enlarge 52KB, 791x1024 3 End-Fed Anti-Symmetric Fractal Bowtie 4nec2 File enlarge 192KB, 1024x734 4 End-Fed Anti-Symmetric Fractal Bowtie Raw Gain 300-1000 MHz enlarge 214KB, 1024x734 5 End-Fed Anti-Symmetric Fractal Bowtie SWR (300-ohms) 300-1000 MHz enlarge 296KB, 1024x734 6 End-Fed Anti-Symmetric Fractal Bowtie Impedance 300-1000 MHz enlarge 61KB, 1024x1004 7 End-Fed Symmetric Fractal Bowtie 3D View enlarge 338KB, 1024x1004 8 End-Fed Symmetric Fractal Bowtie Front View [1 big box = 1.25 inches] enlarge 52KB, 791x1024 9 End-Fed Symmetric Fractal Bowtie 4nec2 File enlarge 197KB, 1024x734 10 End-Fed Symmetric Fractal Bowtie Raw Gain 300-1000 MHz enlarge 212KB, 1024x734 11 End-Fed Symmetric Fractal Bowtie SWR (300-ohms) 300-1000 MHz enlarge 294KB, 1024x734 12 End-Fed Symmetric Fractal Bowtie Impedance 300-1000 MHz enlarge 64KB, 1024x1004 13 Center-Fed Symmetric Fractal Bowtie 3D View enlarge 335KB, 1024x1004 14 Center-Fed Symmetric Fractal Bowtie Front View [1 big box = 1.25 inches] enlarge 45KB, 791x1024 15 Center-Fed Symmetric Fractal Bowtie 4nec2 File enlarge 203KB, 1024x734 16 Center-Fed Symmetric Fractal Bowtie Raw Gain 300-1000 MHz enlarge 215KB, 1024x734 17 Center-Fed Symmetric Fractal Bowtie SWR (300-ohms) 300-1000 MHz enlarge 301KB, 1024x734 18 Center-Fed Symmetric Fractal Bowtie Impedance 300-1000 MHz
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