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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 + VHF Discone V-POL TRUE-OMNI FM + VHF 8-Spokes Vertically Polarized Discone Antenna analyzed using 4nec2. I determined dimensions mostly via trial and error, resulting in barely acceptable (3:1) SWR on the lowest frequency (88 MHz) and reduced Gain (0 dBi) on the highest frequency (216 MHz). Gain=1.4 dBi in FM Band. [Somewhat larger antenna JUST for FM Band adds 0.2-0.3 dBi.] Presumed use of AWG10 and 60-degree Complimentary Cone Angle measured from the X-Y Plane. [Some references measure Cone Angle to the Z-Axis.] Cone Whisker Length=36-in, Disc Radius=20-in, Feedpoint Gap=2.0-in, Inner Circle Radius=1-in. Polarization is almost completely Vertical. Elevation Gain charts reveal that Gain in FM Band is directed at Horizon (Elev=0-deg). However, in Hi-VHF Band, Gain is significantly below the Horizon...hence the depicted antenna SHOULD be mounted UPSIDE-DOWN from shown. Ditto for commonly encountered off-the-shelf VHF Discone Antennas. Date(s): 26 Aug 2012. Album by holl_ands. 1 - 19 of 19 Total. 6255 Visits.
enlarge 95KB, 861x1024 1 FM + VHF 8-Spoke Discone 3D View enlarge 220KB, 1024x865 2 FM + VHF 8-Spoke Discone Front View [2 big box = 5-inches] enlarge 238KB, 996x1024 3 FM + VHF 8-Spoke Discone Top View [2 big box = 5-inches] enlarge 190KB, 1152x692 4 FM + Hi-VHF 8-Spoke Discone Ch2-13 Raw Gain drops off across Ch7-13 enlarge 213KB, 1152x692 5 FM + Hi-VHF 8-Spoke Discone Ch2-13 SWR (75-ohm) is Good except below FM Band enlarge 260KB, 1152x692 6 FM + Hi-VHF 8-Spoke Discone Ch2-13 Impedance enlarge 302KB, 1024x1024 7 FM + Hi-VHF 8-Spoke Discone Azimuthal Pattern on 54 MHz (Ch2) enlarge 300KB, 1024x1024 8 FM + Hi-VHF 8-Spoke Discone Azimuthal Pattern on 90 MHz (Low FM) enlarge 301KB, 1024x1024 9 FM + Hi-VHF 8-Spoke Discone Azimuthal Pattern on 108 MHz (HighFM) enlarge 308KB, 1024x1024 10 FM + Hi-VHF 8-Spoke Discone Azimuthal Pattern on 174 MHz (Ch7) enlarge 306KB, 1024x1024 11 FM + Hi-VHF 8-Spoke Discone Azimuthal Pattern on 198 MHz (Ch10) enlarge 307KB, 1024x1024 12 FM + Hi-VHF 8-Spoke Discone Azimuthal Pattern on 216 MHz (Ch13) enlarge 314KB, 1024x1024 13 FM + Hi-VHF 8-Spoke Discone Elevation Pattern on 54 MHz (Ch2) enlarge 314KB, 1024x1024 14 FM + Hi-VHF 8-Spoke Discone Elevation Pattern on 90 MHz (Low FM) enlarge 320KB, 1024x1024 15 FM + Hi-VHF 8-Spoke Discone Elevation Pattern on 108 MHz (High FM) enlarge 324KB, 1024x1024 16 FM + Hi-VHF 8-Spoke Discone Elevation Pattern on 174 MHz (Ch7) enlarge 324KB, 1024x1024 17 FM + Hi-VHF 8-Spoke Discone Elevation Pattern on 198 MHz (Ch10) enlarge 326KB, 1024x1024 18 FM + Hi-VHF 8-Spoke Discone Elevation Pattern on 216 MHz (Ch13) enlarge 31KB, 791x1024 19 FM + Hi-VHF 8-Spoke Discone 4nec2 File
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