UHF Vertical 8-Bay FAT Dipole with 43 Pairs of Reflector Rods analyzed using 4nec2 after determining Dimensions using nikiml's Optimization Scripts. For some unknown reason, Hi-VHF analysis refused to run correctly, even after trying various AUTOSEG(xx) values.
UHF Raw Gain = 13.4 to 17.1 to 16.2 dBi, F/B & F/R Min = 14.3 dB and SWR (300-ohms) under 3.1.
Compared to NO-MIDDLE-GAP version, Raw Gain improved by an inconsequential 0.1 dB except on the highest frequencies it improved by 0.8 dB. OTOH, hote that SWR, F/B & F/R Ratio were degraded.
HOWEVER, note that when (and if) I rerun this Optimization with a revised Target Function to hopefully adjust SWR below desired limit of 2.7, Gain advantage will no doubt shrink.
ASSUMED DIMENSIONS (in inches): Rdip=0.4375 = Radius of Dipole Elements (7/8-in O.D.) Rfeed=0.06425 = Radius of Feedlines (AWG8) Rrod=0.1875 = Radius of Reflector Rods (3/8-in O.D.) Hop=1.0 = X-Axis Separation at the Cross-Over Cond=2e+07 = Conductivity for Aluminum DSwp=0 = Dipole Forward Sweep (NOT USED IN THIS MODEL]
OPTIMIZED DIMENSIONS (in inches, rounded to nearest 1/8-in): DDSep=9.0 = Dipole-To-Dipole Separation DLen=7.875 = Dipole Half-Length (JUST THE TUBE) FeedSep=2.125 = Separation between two FEEDLINE wires ZCross=1.375 = From Center of Feedline Cross-Over to Center of OUTER Dipoles RS=4.75 = Reflector Rod Separation behind Dipoles RR=1.5 = Reflector Rod-to-Rod Separation YRod=16.785 = Reflector Rod Half-Lengths Rgap=0.25 = Gap Between each Reflector Rod Pair
Date(s): 1 Sep 2014. Album by holl_ands. 1 - 15 of 15 Total. 4559 Visits.
enlarge 207KB, 636x1024 1 UHF Vert 8-Bay Dipole + 43 Pair RR - OPT 3D View
enlarge 264KB, 701x1024 2 UHF Vertical 8-Bay Dipoles + 43 Pair RR Front View There is a 0.25-in Gap at Middle of each RR [1 large square = 5 inches]
enlarge 114KB, 503x1024 3 UHF Vertical 8-Bay Dipoles + 43 Pair RR Top View There is a 0.25-in Gap at Middle of each RR [1 large square = 5 inches]
enlarge 178KB, 1024x690 4 UHF Vertical 8-Bay Dipoles + 43 Pair RR UHF Raw Gain = 13.4 to 17.1 to 16.2 dBi UHF F/B & F/R Minimum = 14.3 dB
