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U+H 2-Bay Hentenna NO+11ReflRods
UHF (+ Hi-VHF) 2-Bay Hentenna with NO Reflector and with 11 Reflector Rods analyzed using 4nec2.

a) UHF 2-Bay Hentenna with NO Reflector:
Analyzed Xauto's version x1052 2-Bay Hentenna: 8.75-in Width x 13-in Height.
Raw Gain = 3.8-5.7 dBi, SWR under 1.8.

b) UHF 2-Bay Hentenna with with 11 Reflector Rods:
dcartier's original 4nec2 file (UHF Gain & SWR Optimized: Score=1.16102) was run for another 30 hours
of optimization (Score=0.660617), using nikiml's Python Scrips, significantly improving F/B & F/R Ratios.

UHF Raw Gain increased about 0.5 dBi.  SWR slightly improved from under 2.2 to under 1.8.
F/B and F/R were significantly improved, from a range of 3-7 dB to a range of 7-13 dB.

Hi-VHF Raw Gain was 7.1-5.5 dBi FORWARD and 7.1-8.2 dBi towards the REVERSE.
Unfortunately SWR was very excessive (25-35).

FYI: Temporarily removing GW40 (wire only 0.5-in behind the feedpoint) increases SWR to 4.3.
I've seen this sort of closely coupled "SWR tuning element" technique used in Yagi Antennas,
including the YA-1713:

BTW: I temporarily commented out GW49 & GW50 (small, upper & lower most Reflector Rods)
and reran 4nec2. I was surprised to see that SWR was unchanged, but Gain increased
about 0.5 dBi and F/B & F/R Ratios were slightly improved....so, there may be TOO many
Reflector Rods....go figure....

More (or Fewer?) Reflector Rods may be required to improve the UHF F/R & F/B Ratios...
It is left as an exercise to optimize both UHF and Hi-VHF...preferably, including
both F/R & F/B Ratios explicitly in the "cost function"....longer runs might also help....

EDIT (5Sep2011): Added UHF 2-Bay Hentenna (Square Loop) with NO Reflector.
Date(s): 21 Aug 2011. Album by holl_ands. 1 - 30 of 30 Total. 10834 Visits.
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UHF 2-Bay Hentenna with NO Reflector
3D View


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UHF 2-Bay Hentenna with NO Reflector
8.75-inch Width x 13.0-inch Height
[1 small box = 0.25-inch]
[1 big box = 0.25-inch]


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3
Twin-Hoop Chireix vs "Figure-8" Twin-Loop
vs Shorted-Bowtie-Loop (SBL) vs 2-Bay Hentenna
vs 6-Whisker Bowtie vs Single Loop.
In decreasing UHF Gain order.


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UHF 2-Bay Hentenna with NO Reflector
UHF Raw Gain = 3.8 to 5.7 dBi


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UHF 2-Bay Hentenna with NO Reflector
UHF SWR (300-ohnms) under 1.8


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UHF 2-Bay Hentenna with NO Reflector
UHF Impedance


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UHF 2-Bay Hentenna with NO Reflector
Azimuthal Pattern at 470 MHz


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UHF 2-Bay Hentenna with NO Reflector
Azimuthal Pattern at 590 MHz


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UHF 2-Bay Hentenna with NO Reflector
Azimuthal Pattern at 698 MHz


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Two-Bay Hentenna with 11 Reflector Rods
holl_ands mods to dcartier 4nec2 file
3D View


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Two-Bay Hentenna with 11 Reflector Rods
Front View
[1 small box = 1-inch]
[1 big box = 5-inches]


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Two-Bay Hentenna with 11 Reflector Rods
Side View
[1 small box = 1-inch]
[1 big box = 5-inches]


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Two-Bay Hentenna with 11 Reflector Rods
UHF Raw Gain


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Two-Bay Hentenna with 11 Reflector Rods
UHF SWR (300-ohm) under 1.8


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Two-Bay Hentenna with 11 Reflector Rods
UHF Impedance


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Two-Bay Hentenna with 11 Reflector Rods
Azimuthal Pattern on 470 MHz


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Two-Bay Hentenna with 11 Reflector Rods
Azimuthal Pattern on 590 MHz


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Two-Bay Hentenna with 11 Reflector Rods
Azimuthal Pattern on 698 MHz


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Two-Bay Hentenna with 11 Reflector Rods
Azimuthal Pattern on 758 MHz


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Two-Bay Hentenna with 11 Reflector Rods
Azimuthal Pattern on 806 MHz


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Two-Bay Hentenna with 11 Reflector Rods
Top View
[1 small box = 0.5-inch]
[1 big box = 2.5-inches]


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Two-Bay Hentenna with 11 Reflector Rods
Hi-VHF Raw Gain
Directed more to REAR on higher channels.


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Two-Bay Hentenna with 11 Reflector Rods
Hi-VHF SWR (300-ohm) is EXCESSIVE


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Two-Bay Hentenna with 11 Reflector Rods
Hi-VHF Impedance


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Two-Bay Hentenna with 11 Reflector Rods
Azimuthal Pattern on 174 MHz


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Two-Bay Hentenna with 11 Reflector Rods
Azimuthal Pattern on 198 MHz


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Two-Bay Hentenna with 11 Reflector Rods - holl_ands
Azimuthal Pattern on 216 MHz


Enlarge Microsoft Word Document 28
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Two-Bay Hentenna with NO Reflector - XAuto
4nec2 File


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DOC29
Two-Bay Hentenna with 11 Reflector Rods
4nec2 File - holl_ands mod to dcartier


Enlarge Microsoft Excel Spreadsheet 30
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XLS30
Two-Bay Hentenna with 11 Reflector Rods
Results Summary Spread Sheet


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