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LoVHF+FM Hourglass Loop
Ch2-6 + FM Hourglass Loop analyzed using 4nec2 after finding "best" dimensions using nikiml's Optimization Scripts.
Based on UHF Hourglass Loop posted by oneolddude in www.digitalhome.ca forum.
Cut a 1-in wide hole in the middle of the 15-in long "Feedpoint Gap" to attach 300:75-ohm Balun Transformer.
Although the below results presumed 0.569-in O.D. Copper Tubing/Pipe, the design is not that
sensitive to wire size.  AWG10 (House Wire) loses 1 dB Raw Gain, with SWR under 2.2.

NO Reflector Rods (Overall 67.5-in H x 87.25-in W, using Half-inch Copper Tubing):
Raw Gain = 3.3-4.5 dBi on Ch2-6, rising to 5.5 dBi across FM Band.
Gain Loss across Ch8-13 is due to Azimuth moving to diagonals.
Excellent SWR on all channels.

CONSTRUCTION HINT:
I would use 3/4-in PVC tubes (white sprinkler or grey PVC electrical conduit if Outdoors) in a
Rectangle a bit bigger than Antenna, held together with 90-deg Elbows PLUS 4 Tie Wraps through holes.
For rigidity, I would add TWO more horizontal cross pieces at about 1/3 and 2/3 height levels.
PVC Glue should be used ONLY on the Elbows and TEE's where they connect to the HORIZONTAL pieces,
with NO GLUE on the Vertical pieces to facilitate assembly on the Ground and partial disassembly
into a tight bundle that can be feed up through an Attic Entry Hole.  Glue MAY NOT be needed once
re-assembled in the Attic....or perhaps use small globs of RTV that can be cut if need be.
Date(s): 29 Nov 2012. Album by holl_ands. 1 - 18 of 18 Total. 0 Visits.
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Lo-VHF+FM Hourglass Loop
3D View
Half-inch Copper Tubing, smaller reduces performance


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Lo-VHF+FM Hourglass Loop
Front View
Overall: 67.5-in H x 87.25-in W
Diagonals = 49.44-in [49.5 is OK]
Feedpoint Gap = 15.0-in
[1 large box = 12.5 inches]


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Lo-VHF+FM Hourglass Loop
4nec2 File


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Lo-VHF+FM Hourglass Loop
Ch2-13 Raw Gain

Hi-VHF Gain moves to the DIAGONALS, see Patterns below


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Lo-VHF+FM Hourglass Loop
Ch2-13 SWR (300-ohm) is Excellent on ALL channels


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Lo-VHF+FM Hourglass Loop
Ch2-13 Impedance


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Lo-VHF+FM Hourglass Loop
Azimuthal Pattern on 54 MHz (Ch2)


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Lo-VHF+FM Hourglass Loop
Azimuthal Pattern on 72 MHz (Ch4)


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Lo-VHF+FM Hourglass Loop
Azimuthal Pattern on 84 MHz (Ch6)


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Lo-VHF+FM Hourglass Loop
Azimuthal Pattern on 90 MHz (Low FM)


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Lo-VHF+FM Hourglass Loop
Azimuthal Pattern on 99 MHz (Mid FM)


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Lo-VHF+FM Hourglass Loop
Azimuthal Pattern on 108 MHz (High FM)


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Lo-VHF+FM Hourglass Loop
Azimuthal Pattern on 174 MHz


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Lo-VHF+FM Hourglass Loop
Azimuthal Pattern on 186 MHz


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Lo-VHF+FM Hourglass Loop
Azimuthal Pattern on 198 MHz


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Lo-VHF+FM Hourglass Loop
Azimuthal Pattern on 210 MHz


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Lo-VHF+FM Hourglass Loop
Azimuthal Pattern on 216 MHz


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Lo-VHF+FM Hourglass Loop
Python Optimization Control *.bat File


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