• Public Gallery  • Help  
• Join Now!  • Log In  • Feature Tour
 holl_ands | Home > Loop Antennas incl Folded Dipole > 
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. 12807 Visits.
Start SlideshowTo order prints and photo-products: 1. Select photos. 2. Click Order. 3. Select products.Select images and click to download to your computer 
Enlarge photo 1
enlarge 0KB, 1024x696
1
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.


Enlarge photo 2
enlarge 0KB, 1024x696
2
UHF Circular Loop - Compare for QICT

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


Enlarge photo 3
enlarge 283KB, 1024x696
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.


Enlarge photo 4
enlarge 0KB, 1024x819
4
UHF Circular Loop - Raw Gain
7.5-in Diameter using AWG12


Enlarge photo 5
enlarge 0KB, 1024x819
5
UHF Circular Loop - SWR
7.5-in Diameter using AWG12


Enlarge photo 6
enlarge 0KB, 1024x819
6
UHF Circular Loop - Impedance
7.5-in Diameter using AWG12


Enlarge photo 7
enlarge 0KB, 1024x819
7
UHF Circular Loop - Raw Gain
8.5-in Diameter using QICT


Enlarge photo 8
enlarge 0KB, 1024x819
8
UHF Circular Loop - SWR
8.5-in Diameter using QICT


Enlarge photo 9
enlarge 0KB, 1024x819
9
UHF Circular Loop - Impedance
8.5-in Diameter using QICT


Enlarge photo 10
enlarge 153KB, 1024x793
10
UHF Circular Loop - Total Gain at 550 MHz
7.5-in Diameter using AWG12


Enlarge photo 11
enlarge 149KB, 1024x791
11
UHF Circular Loop - Total Gain at 650 MHz
7.5-in Diameter using AWG12


Enlarge photo 12
enlarge 150KB, 1024x781
12
UHF Circular Loop - Total Gain at 800 MHz
7.5-in Diameter using AWG12


Enlarge photo 13
enlarge 0KB, 1024x819
13
UHF Circular Loop - Horizontal Gain at 550 MHz
7.5-in Diameter using AWG12


Enlarge photo 14
enlarge 0KB, 1024x819
14
UHF Circular Loop - Horizontal Gain at 650 MHz
7.5-in Diameter using AWG12


Enlarge photo 15
enlarge 0KB, 1024x819
15
UHF Circular Loop - Horizontal Gain at 800 MHz
7.5-in Diameter using AWG12


Enlarge photo 16
enlarge 0KB, 1024x819
16
UHF Circular Loop - Vertical Gain at 550 MHz
7.5-in Diameter using AWG12

Small OVERHEAD Gain at low Freqs.


Enlarge photo 17
enlarge 0KB, 1024x819
17
UHF Circular Loop - Vertical Gain at 650 MHz
7.5-in Diameter using AWG12

OVERHEAD Gain getting smaller.


Enlarge photo 18
enlarge 0KB, 1024x819
18
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.


Enlarge photo 19
enlarge 308KB, 1024x1024
19
UHF Circular Loop - Elevation Gain at 470 MHz
7.5-in Diameter using AWG12


Enlarge photo 20
enlarge 310KB, 1024x1024
20
UHF Circular Loop - Elevation Gain at 650 MHz
7.5-in Diameter using AWG12


Enlarge photo 21
enlarge 320KB, 1024x1024
21
UHF Circular Loop - Elevation Gain at 806 MHz
7.5-in Diameter using AWG12


Enlarge photo 22
enlarge 153KB, 1024x690
22
UHF Circular Loop
7.5-in Diameter using AWG12
Hi-VHF Raw Gain = 0.0 to -1.0 dBi


Enlarge photo 23
enlarge 184KB, 1024x690
23
UHF Circular Loop
7.5-in Diameter using AWG12
Hi-VHF SWR (300-ohms) = 265 to 140 is Excessive


Enlarge photo 24
enlarge 220KB, 1024x690
24
UHF Circular Loop
7.5-in Diameter using AWG12
Hi-VHF Impedance


Enlarge photo 25
enlarge 44KB, 869x1024
25
UHF Square Loop - 6.9-in Per Side, QICT
3D View


Enlarge photo 26
enlarge 187KB, 1024x908
26
UHF Square Loop - 6.9-in Per Side, QICT
Front View
[1 small box = 0.25-in]
[1 big box = 1.25-in]


Enlarge Microsoft Word Document 27
enlarge 26KB, 791x1024
DOC27
UHF Square Loop - 6.9-in Per Side, QICT
4nec2 File


Enlarge photo 28
enlarge 146KB, 1152x638
28
UHF Square Loop - 6.9-in Per Side, QICT
UHF Raw Gain


Enlarge photo 29
enlarge 194KB, 1152x638
29
UHF Square Loop - 6.9-in Per Side, QICT
UHF SWR (300-ohms) under 2.7


Enlarge photo 30
enlarge 161KB, 1152x638
30
UHF Square Loop - 6.9-in Per Side, QICT
UHF Impedance


Enlarge photo 31
enlarge 336KB, 1024x1024
31
UHF Square Loop - 6.9-in Per Side, QICT
Azimuthal Pattern at 470 MHz:
Total, Horizontal & Vertical.


Enlarge photo 32
enlarge 342KB, 1024x1024
32
UHF Square Loop - 6.9-in Per Side, QICT
Azimuthal Pattern at 590 MHz:
Total, Horizontal & Vertical.


Enlarge photo 33
enlarge 346KB, 1024x1024
33
UHF Square Loop - 6.9-in Per Side, QICT
Azimuthal Pattern at 698 MHz:
Total, Horizontal & Vertical.


Enlarge photo 34
enlarge 344KB, 1024x1024
34
UHF Square Loop - 6.9-in Per Side, QICT
Azimuthal Pattern at 758 MHz:
Total, Horizontal & Vertical.
Gain is mostly Vertical, towards sides.


Enlarge photo 35
enlarge 340KB, 1024x1024
35
UHF Square Loop - 6.9-in Per Side, QICT
Azimuthal Pattern at 792 MHz:
Total, Horizontal & Vertical.
Gain is mostly Vertical, towards sides.


Enlarge photo 36
enlarge 355KB, 1024x1024
36
UHF Square Loop - 6.9-in Per Side, QICT
Azimuthal Pattern at 806 MHz:
Total, Horizontal & Vertical.
Gain is mostly Vertical, towards sides.


Enlarge Microsoft Word Document 37
enlarge 25KB, 791x1024
DOC37
Example 4nec2 File
UHF Circular Loop - 8.5-in QICT


 
 Select All.  
  Sign the Guestbook. Displaying 1 of 1 entries.
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