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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 Cycloid Dipole - Circular Polarized FM Cycloid Dipole Omni Antenna with Circular Polarization analyzed using 4nec2. For more info re Cycloid, see: http://www.wa7x.com/cycloid_info.html Although Raw Gain Vertical, Horizontal and TOTAL (Vertical + Horizontal) Polarization was fairly constant across all angles and frequencies, the Impedance varied considerably.  It was 9.2+127j ohms at 87 MHz, rising to 37+410j ohms at 108 MHz, making it very difficult to design a wide-band matching network. Best SWR was about 30:1 with 186-ohm load.  Although Analog FM is tolerant of high SWR, Digital FM may not be. Suppression of Left Hand Circular Polarization (LHCP) is very good across entire FM Band. Intended for broadcast applications, this (and similar) antennas can be matched to 50-ohms (or 300-ohms) for a NARROW RANGE OF FREQUENCIES by using a matching network (hit "F10" key, L/Pi/T Matching in 4nec2). Matched SWR Chart (at bottom) was the SAME, with ANY of the L, Pi or T Filters - Low or High Pass. Date(s): 29 Dec 2011. Album by holl_ands. 1 - 23 of 23 Total. 9919 Visits.
enlarge 42KB, 942x1024 1 FM Cycloid Dipole - Circular Polarized 3D View enlarge 207KB, 814x1024 2 FM Cycloid Dipole - Circular Polarized Front View [1 small box = 2.5-inches] enlarge 173KB, 752x1024 3 FM Cycloid Dipole - Circular Polarized Top View [1 small box = 2.5-inches] enlarge 143KB, 1152x584 4 FM Cycloid Dipole - Circular Polarized FM TOTAL Raw Gain FORWARD (90-deg) enlarge 155KB, 1152x584 5 FM Cycloid Dipole - Circular Polarized FM TOTAL Raw Gain on DIAGONAL (275-deg) enlarge 161KB, 1152x584 6 FM Cycloid Dipole - Circular Polarized FM SWR (186-ohms Optimum) is Excessive 30:1 enlarge 187KB, 1152x584 7 FM Cycloid Dipole - Circular Polarized FM SWR (300-ohms) is Excessive enlarge 167KB, 1152x584 8 FM Cycloid Dipole - Circular Polarized FM SWR (75-ohms) is Excessive enlarge 156KB, 599x1024 9 FM Cycloid Dipole - Circular Polarized Front View [1 small box = 2.5-inches] enlarge 326KB, 1024x1024 10 FM Cycloid Dipole - Circular Polarized Azimuthal Patterns at 87 MHz enlarge 323KB, 1024x1024 11 FM Cycloid Dipole - Circular Polarized Azimuthal Patterns at 92 MHz enlarge 321KB, 1024x1024 12 FM Cycloid Dipole - Circular Polarized Azimuthal Patterns at 97 MHz enlarge 320KB, 1024x1024 13 FM Cycloid Dipole - Circular Polarized Azimuthal Patterns at 103 MHz Cir. Pol. beginning to degrade. enlarge 324KB, 1024x1024 14 FM Cycloid Dipole - Circular Polarized Azimuthal Patterns at 108 MHz Cir. Pol. is degraded. enlarge 26KB, 791x1024 15 FM Cycloid Dipole - Circular Polarized 4nec2 File enlarge 317KB, 1024x1024 16 FM Cycloid Dipole - Circular Polarized Circular Polarization Patterns at 87 MHz enlarge 313KB, 1024x1024 17 FM Cycloid Dipole - Circular Polarized Circular Polarization Patterns at 92 MHz enlarge 305KB, 1024x1024 18 FM Cycloid Dipole - Circular Polarized Circular Polarization Patterns at 98 MHz enlarge 303KB, 1024x1024 19 FM Cycloid Dipole - Circular Polarized Circular Polarization Patterns at 103 MHz enlarge 313KB, 1024x1024 20 FM Cycloid Dipole - Circular Polarized Circular Polarization Patterns at 108 MHz enlarge 186KB, 1024x1024 21 FM Cycloid Dipole - Circular Polarized Circular Polarization Patterns - Ani-Gif enlarge 216KB, 1024x927 22 FM Cycloid Dipole - Circular Polarized Must run 4nec2 file before select "F10". Make "RLC Matching (F10)" entries then click on "Use Network". "Z-Load" comes from Impedance Chart at 98 MHz. enlarge 197KB, 1152x584 23 FM Cycloid Dipole - Circular Polarized FM SWR (300-ohms) is Very Narrowband When using Matching Network. Results are SAME, with L, Pi or T Filters - Low or High Pass.
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