FM Double-Hoop plus Vertical Dipole Outside analyzed using 4nec2.
This antenna responds to both Horizontal and Vertical Polarization, although they are only have equal Raw Gain at about 97 MHz. Below 97 MHz, Vertical Gain is reduced by more than 10 dB and above 97 MHz Horizontal Gain is reduced by more than 10 dB. However, Total Gain (Vert. + Horiz.) remained between -1.9 and +2.1 dBi across all angles and frequencies. SWR (75-ohms) was under 5. SWR (300-ohms) was excessive on the lowest frequencies.
Although Raw Gain varies quite a bit, the Omni-Directional azimuthal coverage remains very consistent across all angles. However, users may be unhappy with performance if a station is only transmitting one Polarity.
17 Dec 201115 items4625 visitsAlbum by holl_ands
enlarge 71KB, 726x1024 1 FM Double-Hoop + Vertical-Dipole 3D View
enlarge 145KB, 563x1024 2 FM Double-Hoop + Vertical-Dipole Front View [1 big box = 5-inches]
enlarge 260KB, 1024x974 3 FM Double-Hoop + Vertical-Dipole Top View [1 big box = 2.5-inches]
enlarge 183KB, 1152x584 4 FM Double-Hoop + Vertical-Dipole FM Total Raw Gain FORWARD
enlarge 146KB, 1152x584 5 FM Double-Hoop + Vertical-Dipole FM Total Raw Gain to SIDE (0-deg)
enlarge 178KB, 1152x584 6 FM Double-Hoop + Vertical-Dipole FM SWR (300-ohms) Excessive on Low Freqs
enlarge 187KB, 1152x584 7 FM Double-Hoop + Vertical-Dipole FM SWR (75-ohms) Under 5.0
enlarge 158KB, 1152x584 8 FM Double-Hoop + Vertical-Dipole FM Impedance
enlarge 144KB, 560x1024 9 FM Double-Hoop + Vertical-Dipole Side View [1 big box = 5-inches]
enlarge 333KB, 1024x1024 10 FM Double-Hoop + Vertical-Dipole Azimuthal Pattern at 87 MHz
enlarge 315KB, 1024x1024 11 FM Double-Hoop + Vertical-Dipole Azimuthal Pattern at 91 MHz
enlarge 334KB, 1024x1024 12 FM Double-Hoop + Vertical-Dipole Azimuthal Pattern at 97 MHz
enlarge 334KB, 1024x1024 13 FM Double-Hoop + Vertical-Dipole Azimuthal Pattern at 103 MHz
enlarge 317KB, 1024x1024 14 FM Double-Hoop + Vertical-Dipole Azimuthal Pattern at 108 MHz
enlarge 48KB, 791x1024 15 FM Double-Hoop + Vertical-Dipole 4nec2 File
