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holl_ands | Home > Omni & Quasi-Omni Directional Antennas > Browse:FM Flat-Swept SBGH H-POL OMNI-PLUSFM TRIAD 4xRectangular-Loops H-OMNI-PLUSFM Goalkeeper Quad-Trap+Spurs Quasi-OMNIFM TRIAD Array of Dipoles H-OMNIFM Double-Hoop H-POL OMNIFM Double-Hoop + Vertical-Dipole OutsideFM Double-Hoop + Vertical-FD-OutsideFM Double-Hoop + Vert. Dipole In CenterFM Double-Hoop + Vertical-FD-In-CenterFM Double-Hoop + Vertical Whip OutsideFM Vertical Folded Dipole VPOL TRUE-OMNIFM Vertical Stick Dipole V-POL TRUE-OMNIFM + VHF Discone V-POL TRUE-OMNIFM Monopole Whip over Groundplane OMNIFM Turnstile QuasiOMNI Antennacraft FMSSFM Turnstile Quasi-Omni - AlternateFM Turnstile - A-C FMSS RotatedFM ESS Curves - Fracarro & DipolFM ZigZag - Triax FM ZigmaFM Right Circular Folded Dipole PairFM Cycloid Dipole - Circular Polarized490 MHz Flat-Swept SBGH H-POL OMNI-PLUS490 MHz Flat-Swept SBGH OMNI + TOP-HAT490 MHz 3-Dipole TRIAD Array H-POL OMNI490 MHz Crossed-Dipoles + One TL - OMNI490 MHz Crossed-Dipoles, 2 Unequal TLs490 MHz 7-El Yagi TRIAD H-POL OMNI-PLUS490 MHz 4El Yagi Triad H-POL True-OMNI490 MHz Collinear Helical HPOL OMNI-PLUS490 MHz Double Diamond H-POL Quasi-OMNIUHF Vertical Folded Dipole V-POL OMNIUHF SBGH H-POL OMNI-PLUS by nikimlUHF Hoverman Type 1 H-POL Quasi-OmniUHF M4 (10x9.5) Twisted 4-Bay Quasi-OMNIUHF 2xM4 Twisted 8-Bay - Quasi-OMNIHi-VHF Goalkeeper Quad-Trapezoid+SpursHi-VHF Monopole Whip V-POL TRUE-OMNIHi-VHF Vertical Folded Dipole OMNICh2-69 Crossed Loops 90-deg Phase ShiftCh2-69 + FM Crossed Loops - UVOX-22m "Classic" 3QWL+QWL J-Pole
FM ZigZag - Triax FM Zigma FM ZigZag Antenna, similar to Triax FM Zigma, analyzed using 4nec2. Triax FM Zigma Specs: Gain = -1.0 dBi, F/B Ratio = 0 dB, Beamwidth = +/- 45-deg (Horizontal Polarization) and +/- 180-deg (Vertical Pol.). Erroneously] "Length" [Width!!!] = 550-mm and "Width" [Height!!!] = 1140-mm: http://www.triax.co.uk/upload/gb_-_triax_main_catalogue_2009.pdf Triax FM Zigma Dimensions: Height = 44.88-in, Width = 21.65-in, Separation = 2.0-in. Separation was a Guesstimate, based on Triax's picture.  If it were 3.0-in, SWR is under 3.5 with negligible change in Gain. Triax FM Zigma 4nec2 Results: For Vertically Polarized signals, the Azimuthal Pattern was close to Omni-directional, varying from -1.5 to -0.7 dBi across all angles and frequencies.  However, for Horizontally Polarized signals, the pattern was Bi-Directional, with deep nulls to the sides (like a Folded Dipole), varying from -39 to -1.7 dBi. Across all angles and frequencies, Total Raw Gain ranges from -1.5 to +2.4 dB (Horizontal + Vertical). SWR (300-ohms) is under 3.7. ============================================================================== A parameter search was conducted to find the dimensions for which the Vert. Pol. Gain was roughly equal to Horiz. Pol. Gain and hence provided optimal response to Circularly Polarized signals.  Results are below. FM ZigZag Cir. Pol. Dimensions: Height = 39-in, Width = 22-in, Separation = 2.0-in. Note that Cir. Pol. condition is only found in the Forward and Reverse directions due to Horiz. Pol. nulls on sides. FM ZigZag 4nec2 Results: For Vertically Polarized signals, the Azimuthal Pattern was close to Omni-directional, varying from -2.5 to -0.4 dBi across all angles and frequencies.  However, for Horizontally Polarized signals, the pattern was Bi-Directional, with deep nulls to the sides (like a Folded Dipole), varying from -37 to -1.1 dBi. Across all angles and frequencies, Total Raw Gain ranges from -2.5 to +2.3 dB (Horizontal + Vertical). SWR (300-ohms) is under 3.7. FYI: There were many nikiml python script solutions with SWR under 3.0, but NONE came close to Cir. Pol. condition. Date(s): 30 Dec 2011. Album by holl_ands. 1 - 26 of 26 Total. 4807 Visits.
enlarge 43KB, 793x1024 1 Triax FM Zigma 3D View enlarge 153KB, 623x1024 2 Triax FM Zigma Front View - 44.9-in High, 21.7-in Wide [1 big box = 5-inches] enlarge 61KB, 213x1024 3 Triax FM Zigma Side View - 2-in Separation between Elements [1 big box = 5-inches] enlarge 143KB, 1152x584 4 Triax FM Zigma FM TOTAL Raw Gain to REVERSE is more than FORWARD enlarge 170KB, 1152x584 5 Triax FM Zigma FM SWR (300-ohms) is Under 3.7 enlarge 156KB, 1152x584 6 Triax FM Zigma FM Impedance enlarge 337KB, 1024x1024 7 Triax FM Zigma Azimuthal Pattern at 87 MHz enlarge 338KB, 1024x1024 8 Triax FM Zigma Azimuthal Pattern at 97 MHz enlarge 339KB, 1024x1024 9 Triax FM Zigma Azimuthal Pattern at 103 MHz enlarge 341KB, 1024x1024 10 Triax FM Zigma Azimuthal Pattern at 108 MHz enlarge 70KB, 263x1024 11 Triax FM Zigma Top View - 2.0-in Separation between Elements [1 big box = 2.5-inches] enlarge 26KB, 791x1024 12 Triax FM Zigma 4nec2 File enlarge 35KB, 642x1024 13 FM ZigZag - Cir. Pol Fwd/Rev 3D View enlarge 157KB, 686x1024 14 FM ZigZag - Cir. Pol Fwd/Rev Front View - 39-in Height, 22-in Width [1 big box = 5-inches] enlarge 58KB, 225x1024 15 FM ZigZag - Cir. Pol Fwd/Rev Side View - 2-in Separation between Elements [1 big box = 5-inches] enlarge 152KB, 1152x584 16 FM ZigZag - Cir. Pol Fwd/Rev FM TOTAL Raw Gain to REVERSE is more than FORWARD enlarge 134KB, 1152x584 17 FM ZigZag - Cir. Pol Fwd/Rev FM TOTAL (Vert. + Horiz.) Raw Gain to SIDES is never below -2.5 dBi, despite Horiz. Pol. nulls. enlarge 169KB, 1152x584 18 FM ZigZag - Cir. Pol Fwd/Rev FM SWR (300-ohms) is under 3.7 enlarge 156KB, 1152x584 19 FM ZigZag - Cir. Pol Fwd/Rev FM Impedance enlarge 334KB, 1024x1024 20 FM ZigZag - Cir. Pol Fwd/Rev Azimuthal Pattern at 87 MHz enlarge 333KB, 1024x1024 21 FM ZigZag - Cir. Pol Fwd/Rev Azimuthal Pattern at 91 MHz enlarge 334KB, 1024x1024 22 FM ZigZag - Cir. Pol Fwd/Rev Azimuthal Pattern at 97 MHz enlarge 334KB, 1024x1024 23 FM ZigZag - Cir. Pol Fwd/Rev Azimuthal Pattern at 103 MHz enlarge 337KB, 1024x1024 24 FM ZigZag - Cir. Pol Fwd/Rev Azimuthal Pattern at 108 MHz enlarge 26KB, 791x1024 25 FM ZigZag - Cir. Pol Fwd/Rev 4nec2 File enlarge 65KB, 241x1024 26 FM ZigZag - Cir. Pol Fwd/Rev Top View - 2-in Separation between Elements [1 big box = 2.5-inches]
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