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UHF Circular & Square Loops NO Reflector
UHF Circular & Square Loops analyzed using 4nec2.

a) UHF Circular Loop - NO Reflector:
Ken Nist's Loopa.ez (7.5-in diameter, using AWG12) is a good choice for the Old UHF Band.
A better choice for the (470-698 MHz) UHF Band is 7.75-in diameter, using AWG12.
However, SWR is excessive at lowest and highest frequencies.

SWR can be significantly improved by using QICT (Quarter Inch Copper Tubing), with 8.5-in
Diameter being best size for UHF Band.  Raw Gain is then 3.6-5.1 dBi, SWR under 2.7.

b) UHF Square Loop - NO Reflector
Optimum size for UHF Band is 6.9-in per side (x4).
Raw Gain is 3.4-4.1 dBi.  SWR is under 2.7.  Which is lower Gain than the Circular Loop above.

EDIT (6 Sep 2011): Added UHF Square Loop.
Date(s): 15 July 2009. Album by holl_ands. 1 - 37 of 37 Total. 0 Visits.
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UHF Circular Loop - Compare for AWG12

Ken Nist's Loopa.ez (7.5-in) is good for Old UHF Band.
Slightly larger (7.75-in) is best for New UHF Band.

Click on image to see higher rez.
Click on "X" as usual to exit Window.


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UHF Circular Loop - Compare for QICT

QuarterInchCopperTubing significantly improves SWR.
Best size is 8.5-in for New UHF Band.


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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 Circular Loop - Raw Gain
7.5-in Diameter using AWG12


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UHF Circular Loop - SWR
7.5-in Diameter using AWG12


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UHF Circular Loop - Impedance
7.5-in Diameter using AWG12


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UHF Circular Loop - Raw Gain
8.5-in Diameter using QICT


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UHF Circular Loop - SWR
8.5-in Diameter using QICT


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UHF Circular Loop - Impedance
8.5-in Diameter using QICT


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UHF Circular Loop - Total Gain at 550 MHz
7.5-in Diameter using AWG12


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UHF Circular Loop - Total Gain at 650 MHz
7.5-in Diameter using AWG12


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UHF Circular Loop - Total Gain at 800 MHz
7.5-in Diameter using AWG12


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UHF Circular Loop - Horizontal Gain at 550 MHz
7.5-in Diameter using AWG12


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UHF Circular Loop - Horizontal Gain at 650 MHz
7.5-in Diameter using AWG12


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UHF Circular Loop - Horizontal Gain at 800 MHz
7.5-in Diameter using AWG12


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UHF Circular Loop - Vertical Gain at 550 MHz
7.5-in Diameter using AWG12

Small OVERHEAD Gain at low Freqs.


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UHF Circular Loop - Vertical Gain at 650 MHz
7.5-in Diameter using AWG12

OVERHEAD Gain getting smaller.


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UHF Circular Loop - Vertical Gain at 800 MHz
7.5-in Diameter using AWG12

Moderate Gain towards the SIDES.
But well outside the new UHF Band.


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UHF Circular Loop - Elevation Gain at 470 MHz
7.5-in Diameter using AWG12


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UHF Circular Loop - Elevation Gain at 650 MHz
7.5-in Diameter using AWG12


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UHF Circular Loop - Elevation Gain at 806 MHz
7.5-in Diameter using AWG12


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UHF Circular Loop
7.5-in Diameter using AWG12
Hi-VHF Raw Gain = 0.0 to -1.0 dBi


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UHF Circular Loop
7.5-in Diameter using AWG12
Hi-VHF SWR (300-ohms) = 265 to 140 is Excessive


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UHF Circular Loop
7.5-in Diameter using AWG12
Hi-VHF Impedance


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UHF Square Loop - 6.9-in Per Side, QICT
3D View


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UHF Square Loop - 6.9-in Per Side, QICT
Front View
[1 small box = 0.25-in]
[1 big box = 1.25-in]


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DOC27
UHF Square Loop - 6.9-in Per Side, QICT
4nec2 File


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UHF Square Loop - 6.9-in Per Side, QICT
UHF Raw Gain


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UHF Square Loop - 6.9-in Per Side, QICT
UHF SWR (300-ohms) under 2.7


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UHF Square Loop - 6.9-in Per Side, QICT
UHF Impedance


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UHF Square Loop - 6.9-in Per Side, QICT
Azimuthal Pattern at 470 MHz:
Total, Horizontal & Vertical.


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UHF Square Loop - 6.9-in Per Side, QICT
Azimuthal Pattern at 590 MHz:
Total, Horizontal & Vertical.


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UHF Square Loop - 6.9-in Per Side, QICT
Azimuthal Pattern at 698 MHz:
Total, Horizontal & Vertical.


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UHF Square Loop - 6.9-in Per Side, QICT
Azimuthal Pattern at 758 MHz:
Total, Horizontal & Vertical.
Gain is mostly Vertical, towards sides.


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UHF Square Loop - 6.9-in Per Side, QICT
Azimuthal Pattern at 792 MHz:
Total, Horizontal & Vertical.
Gain is mostly Vertical, towards sides.


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UHF Square Loop - 6.9-in Per Side, QICT
Azimuthal Pattern at 806 MHz:
Total, Horizontal & Vertical.
Gain is mostly Vertical, towards sides.


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DOC37
Example 4nec2 File
UHF Circular Loop - 8.5-in QICT


 
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holl_ands,

Have you done any UHF circular modeling with a screen reflector yet?

What spacing would one use for a 506-698 MHz range?
 - 
Systems2000, Thu, 15 Oct 2009 11:54AM