UHF Free-Form 3-Bay (FF3) analyzed using 4nec2 after determining Dimensions using nikiml's Python Optimization scripts.
Three alternative interconnection Topographies were determined to be of interest for investigation (first below is the BEST). Most Bowtie Parameters were INDEPENDENTLY varied in determining the fol. three versions of the FF3 (Free-Form 3-Bay Bowtie): [BTW: Other Topographies were considered and found to be significantly worse.]
Note that Gain Charts are for TOTAL (Horiz. + Vert.) Gain. Azimuthal Charts show that there is lower, but significant Vertical Gain to the SIDES of the Antenna.
a) Remove Top Bowtie from FF4 (so Offset Feedpoint) and Re-Optimize:
UHF Raw Gain = 8.6 to 11.4 dBi and SWR (300-ohms) Under 2.7 is Good. Hi-VHF Raw Gain = 2.4 to 3.0 dBi and SWR (300-ohms) = 3.9 to 6.3 is Higher than Desired.
b) Move Feedpoint to Inner Bowtie with Crossover Feedlines to each Outer Bowtie, which are presumably needed to ensure all three signals are In-Phase at the Feedpoint:
UHF Raw Gain = 8.1 to 10.1 dBi and SWR (300-ohms) Under 2.6 is Good. Hi-VHF Raw Gain = 2.6 to 2.9 dBi and SWR (300-ohms) = 9.4 to 2.1 is Excessive on Ch7-11.
c) Offset Feedpoint (like a), but with Straight (NO Crossover) Feedlines to each Outer Bowtie:
UHF Raw Gain = 7.1 to 9.4 to 9.1 to 10.7 dBi and SWR (300-ohms) Under 3.1 is a Bit Higher then Desired. Hi-VHF Raw Gain = 2.1 to 2.6 dBi and SWR (300-ohms) = 7.8 to 6.4 is Excessive.
Date(s): 21 Oct 2015. Album by holl_ands. 1 - 87 of 87 Total. 3088 Visits.
enlarge 58KB, 640x1024 1 FF3 = FF4 - Top Bay, Offset FP, NO Refl 3D View
enlarge 274KB, 833x1024 2 FF3 = FF4 - Top Bay, Offset FP, NO Refl Front View [1 large square = 2.5 Inches]
enlarge 88KB, 312x1024 3 FF3 = FF4 - Top Bay, Offset FP, NO Refl Top View [1 large square = 2.5 Inches]
enlarge 159KB, 1024x644 4 FF3 = FF4 - Top Bay, Offset FP, NO Refl UHF Raw Gain = 8.6 to 11.4 dBi
enlarge 179KB, 1024x644 5 FF3 = FF4 - Top Bay, Offset FP, NO Refl UHF SWR (300-ohms) Under 2.7
enlarge 224KB, 1024x644 6 FF3 = FF4 - Top Bay, Offset FP, NO Refl UHF Impedance
enlarge 335KB, 1024x1024 7 FF3 = FF4 - Top Bay, Offset FP, NO Refl Azimuthal Pattern at 470 MHz
enlarge 337KB, 1024x1024 8 FF3 = FF4 - Top Bay, Offset FP, NO Refl Azimuthal Pattern at 530 MHz
enlarge 340KB, 1024x1024 9 FF3 = FF4 - Top Bay, Offset FP, NO Refl Azimuthal Pattern at 590 MHz
enlarge 339KB, 1024x1024 10 FF3 = FF4 - Top Bay, Offset FP, NO Refl Azimuthal Pattern at 650 MHz
enlarge 339KB, 1024x1024 11 FF3 = FF4 - Top Bay, Offset FP, NO Refl Azimuthal Pattern at 698 MHz
enlarge 343KB, 1024x1024 12 FF3 = FF4 - Top Bay, Offset FP, NO Refl Azimuthal Pattern at 806 MHz
enlarge 329KB, 1024x1024 13 FF3 = FF4 - Top Bay, Offset FP, NO Refl Elevation Pattern at 470 MHz
enlarge 342KB, 1024x1024 14 FF3 = FF4 - Top Bay, Offset FP, NO Refl Elevation Pattern at 530 MHz
enlarge 343KB, 1024x1024 15 FF3 = FF4 - Top Bay, Offset FP, NO Refl Elevation Pattern at 590 MHz
enlarge 322KB, 1024x1024 16 FF3 = FF4 - Top Bay, Offset FP, NO Refl Elevation Pattern at 650 MHz
enlarge 325KB, 1024x1024 17 FF3 = FF4 - Top Bay, Offset FP, NO Refl Elevation Pattern at 698 MHz
enlarge 326KB, 1024x1024 18 FF3 = FF4 - Top Bay, Offset FP, NO Refl Elevation Pattern at 806 MHz
enlarge 162KB, 1024x644 19 FF3 = FF4 - Top Bay, Offset FP, NO Refl Hi-VHF Raw Gain = 2.4 to 3.0 dBi
enlarge 192KB, 1024x644 20 FF3 = FF4 - Top Bay, Offset FP, NO Refl Hi-VHF SWR (300-ohms) = 3.9 to 6.3 is Higher than Desired
enlarge 212KB, 1024x644 21 FF3 = FF4 - Top Bay, Offset FP, NO Refl Hi-VHF Impedance
enlarge 334KB, 1024x1024 22 FF3 = FF4 - Top Bay, Offset FP, NO Refl Azimuthal Pattern at 174 MHz
enlarge 335KB, 1024x1024 23 FF3 = FF4 - Top Bay, Offset FP, NO Refl Azimuthal Pattern at 198 MHz
enlarge 338KB, 1024x1024 24 FF3 = FF4 - Top Bay, Offset FP, NO Refl Azimuthal Pattern at 216 MHz
enlarge 326KB, 1024x1024 25 FF3 = FF4 - Top Bay, Offset FP, NO Refl Elevation Pattern at 174 MHz
enlarge 322KB, 1024x1024 26 FF3 = FF4 - Top Bay, Offset FP, NO Refl Elevation Pattern at 198 MHz
enlarge 323KB, 1024x1024 27 FF3 = FF4 - Top Bay, Offset FP, NO Refl Elevation Pattern at 216 MHz
enlarge 36KB, 791x1024 28 FF3 = FF4 - Top Bay, Offset FP, NO Refl 4nec2 File Includes Summary of Dimensions
enlarge 26KB, 791x1024 29 FF3 = FF4 - Top Bay, Offset FP, NO Refl EVAL Summary of Performance
enlarge 41KB, 791x1024 30 FF3 = FF4 - Top Bay, Offset FP, NO Refl EVAL *.html Performance Summary
enlarge 65KB, 677x1024 31 FF3, Central FP, 2 Crossovers, NO Refl 3D View
enlarge 295KB, 1021x1024 32 FF3, Central FP, 2 Crossovers, NO Refl Front View [1 large square = 2.5 Inches]
enlarge 93KB, 347x1024 33 FF3, Central FP, 2 Crossovers, NO Refl Top View [1 large square = 2.5 Inches]
enlarge 160KB, 1024x644 34 FF3, Central FP, 2 Crossovers, NO Refl UHF Raw Gain = 8.1 to 10.1 dBi
enlarge 184KB, 1024x644 35 FF3, Central FP, 2 Crossovers, NO Refl UHF SWR (300-ohms) Under 2.6
enlarge 221KB, 1024x644 36 FF3, Central FP, 2 Crossovers, NO Refl UHF Impedance
enlarge 331KB, 1024x1024 37 FF3, Central FP, 2 Crossovers, NO Refl Azimuthal Pattern at 470 MHz
enlarge 331KB, 1024x1024 38 FF3, Central FP, 2 Crossovers, NO Refl Azimuthal Pattern at 530 MHz
enlarge 329KB, 1024x1024 39 FF3, Central FP, 2 Crossovers, NO Refl Azimuthal Pattern at 590 MHz
enlarge 329KB, 1024x1024 40 FF3, Central FP, 2 Crossovers, NO Refl Azimuthal Pattern at 650 MHz
enlarge 331KB, 1024x1024 41 FF3, Central FP, 2 Crossovers, NO Refl Azimuthal Pattern at 698 MHz
enlarge 337KB, 1024x1024 42 FF3, Central FP, 2 Crossovers, NO Refl Azimuthal Pattern at 806 MHz
enlarge 332KB, 1024x1024 43 FF3, Central FP, 2 Crossovers, NO Refl Elevation Pattern at 470 MHz
enlarge 330KB, 1024x1024 44 FF3, Central FP, 2 Crossovers, NO Refl Elevation Pattern at 590 MHz
enlarge 333KB, 1024x1024 45 FF3, Central FP, 2 Crossovers, NO Refl Elevation Pattern at 806 MHz
enlarge 160KB, 1024x644 46 FF3, Central FP, 2 Crossovers, NO Refl Hi-VHF Raw Gain = 2.6 to 2.9 dBi
enlarge 186KB, 1024x644 47 FF3, Central FP, 2 Crossovers, NO Refl Hi-VHF SWR (300-ohms) = 9.4 to 2.1 is Excessive on Ch7-11
enlarge 209KB, 1024x644 48 FF3, Central FP, 2 Crossovers, NO Refl Hi-VHF Impedance
enlarge 338KB, 1024x1024 49 FF3, Central FP, 2 Crossovers, NO Refl Azimuthal Pattern at 174 MHz
enlarge 338KB, 1024x1024 50 FF3, Central FP, 2 Crossovers, NO Refl Azimuthal Pattern at 198 MHz
enlarge 341KB, 1024x1024 51 FF3, Central FP, 2 Crossovers, NO Refl Azimuthal Pattern at 216 MHz
enlarge 320KB, 1024x1024 52 FF3, Central FP, 2 Crossovers, NO Refl Elevation Pattern at 174 MHz
enlarge 320KB, 1024x1024 53 FF3, Central FP, 2 Crossovers, NO Refl Elevation Pattern at 198 MHz
enlarge 322KB, 1024x1024 54 FF3, Central FP, 2 Crossovers, NO Refl Elevation Pattern at 216 MHz
enlarge 36KB, 791x1024 55 FF3, Central FP, 2 Crossovers, NO Refl 4nec2 File Includes Summary of Dimensions
enlarge 26KB, 791x1024 56 FF3, Central FP, 2 Crossovers, NO Refl EVAL Summary of Performance
enlarge 40KB, 791x1024 57 FF3, Central FP, 2 Crossovers, NO Refl EVAL *.html Performance Summary
enlarge 74KB, 729x1024 58 FF3, Offset FP, NO Crossovers, NO Refl 3D View
enlarge 212KB, 756x1024 59 FF3, Offset FP, NO Crossovers, NO Refl Front View [1 large square = 2.5 Inches]
enlarge 106KB, 459x1024 60 FF3, Offset FP, NO Crossovers, NO Refl Top View [1 large square = 2.5 Inches]
enlarge 157KB, 1024x644 61 FF3, Offset FP, NO Crossovers, NO Refl UHF Raw Gain = 7.1 to 9.4 to 9.1 to 10.7 dBi
enlarge 174KB, 1024x644 62 FF3, Offset FP, NO Crossovers, NO Refl UHF SWR (300-ohms) Under 3.1
enlarge 221KB, 1024x644 63 FF3, Offset FP, NO Crossovers, NO Refl UHF Impedance
enlarge 335KB, 1024x1024 64 FF3, Offset FP, NO Crossovers, NO Refl Azimuthal Pattern at 470 MHz
enlarge 334KB, 1024x1024 65 FF3, Offset FP, NO Crossovers, NO Refl Azimuthal Pattern at 530 MHz
enlarge 331KB, 1024x1024 66 FF3, Offset FP, NO Crossovers, NO Refl Azimuthal Pattern at 590 MHz
enlarge 337KB, 1024x1024 67 FF3, Offset FP, NO Crossovers, NO Refl Azimuthal Pattern at 650 MHz
enlarge 343KB, 1024x1024 68 FF3, Offset FP, NO Crossovers, NO Refl Azimuthal Pattern at 698 MHz
enlarge 337KB, 1024x1024 69 FF3, Offset FP, NO Crossovers, NO Refl Azimuthal Pattern at 806 MHz
enlarge 335KB, 1024x1024 70 FF3, Offset FP, NO Crossovers, NO Refl Elevation Pattern at 470 MHz
enlarge 333KB, 1024x1024 71 FF3, Offset FP, NO Crossovers, NO Refl Elevation Pattern at 530 MHz
enlarge 330KB, 1024x1024 72 FF3, Offset FP, NO Crossovers, NO Refl Elevation Pattern at 590 MHz
enlarge 329KB, 1024x1024 73 FF3, Offset FP, NO Crossovers, NO Refl Elevation Pattern at 650 MHz
enlarge 328KB, 1024x1024 74 FF3, Offset FP, NO Crossovers, NO Refl Elevation Pattern at 698 MHz
enlarge 334KB, 1024x1024 75 FF3, Offset FP, NO Crossovers, NO Refl Elevation Pattern at 806 MHz
enlarge 159KB, 1024x644 76 FF3, Offset FP, NO Crossovers, NO Refl Hi-VHF Raw Gain = 2.1 to 2.6 dBi
enlarge 179KB, 1024x644 77 FF3, Offset FP, NO Crossovers, NO Refl Hi-VHF SWR (300-ohms) = 7.8 to 6.4 is Excessive
enlarge 210KB, 1024x644 78 FF3, Offset FP, NO Crossovers, NO Refl Hi-VHF Impedance
enlarge 321KB, 1024x1024 79 FF3, Offset FP, NO Crossovers, NO Refl Azimuthal Pattern at 174 MHz
enlarge 320KB, 1024x1024 80 FF3, Offset FP, NO Crossovers, NO Refl Azimuthal Pattern at 198 MHz
enlarge 329KB, 1024x1024 81 FF3, Offset FP, NO Crossovers, NO Refl Azimuthal Pattern at 216 MHz
enlarge 315KB, 1024x1024 82 FF3, Offset FP, NO Crossovers, NO Refl Elevation Pattern at 174 MHz
enlarge 314KB, 1024x1024 83 FF3, Offset FP, NO Crossovers, NO Refl Elevation Pattern at 198 MHz
enlarge 317KB, 1024x1024 84 FF3, Offset FP, NO Crossovers, NO Refl Elevation Pattern at 216 MHz
enlarge 36KB, 791x1024 85 FF3, Offset FP, NO Crossovers, NO Refl 4nec2 File Includes Summary of Dimensions
enlarge 26KB, 791x1024 86 FF3, Offset FP, NO Crossovers, NO Refl EVAL Summary of Performance
enlarge 31KB, 791x1024 87 FF3, Offset FP, NO Crossovers, NO Refl EVAL *.html Performance Summary
