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Arts and Crafts
16 - 30 of 643 Total. Shared
UHF 13-El Twin-Boom LPDA - OPT
16. UHF 13-El Twin-Boom LPDA - OPT  (13 May 2015)
UHF 13-Element Twin-Boom (Layered) LPDA (Log Periodic Dipole Array) with Dimensions Optimized
for Highest Gain (i.e. Sigma = 0.18) using nikiml's Python Scripts.
Boom-Length = 36.7-inches.

UHF Raw Gain = 10.6 to 11.0 to 10.2 to 10.6 dBi, F/B & F/R Ratio Min = 25.0 dB and SWR (75-ohms) under 1.6.

Note that Max UHF Raw Gain occurs when Sigma = 0.213 (per Optimization) and 0.22 (per Parameter Study),
but Quasi-Optimum Sigma = 0.18 is nearly SAME Performance, with much shorter Length, as analyzed here.

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102 Visits
22 Images
Linked Album
holl_ands
Ch45-51 12-El FD-Yagi - OPTimized
17. Ch45-51 12-El FD-Yagi - OPTimized  (11 May 2015)
Ch45-51 12-Element Folded Dipole Yagi with Optimized Dimensions using nikiml's Python Scripts.  BoomLength = 48.3-in.
125 Visits
15 Images
Linked Album
holl_ands
Hi-VHF 22-El FD-Yagi - OPTimized
18. Hi-VHF 22-El FD-Yagi - OPTimized  (10 May 2015)
Hi-VHF 22-Element Folded Dipole Yagi with Optimized Dimensions determined using nikiml's Python Scripts.
Boom-Length = 217-in (about 18-ft).

Hi-VHF Raw Gain = 12.5 to 15.2 to 13.9 dBi, F/B & F/R Min = 24.0 dB and SWR (300-ohms) Under 2.2.
153 Visits
12 Images
Linked Album
holl_ands
Jewelry Organizer-Holder
19. Jewelry Organizer-Holder  (May 3, 2015)
210 Visits
34 Images
Linked Album
wildrainsphynx
Support the Troops
20. Support the Troops 
122 Visits
5 Images
Linked Album
fulks19
UHF 7-El Wedge & Layered LPDA
21. UHF 7-El Wedge & Layered LPDA  (27 Apr 2015)
UHF 7-Element Layered LPDA (Log Periodic Dipole Array with Top and Bottom Arrays parallel to each other)
was found after trying to Optimize the Wedge version (with Inclusive Angle = 2* HalfAngle) and finding that
it was essentially a Layered version...which was then partially Re-Optimized to find the "best" Separation
between the Top and Bottom set of LPDA Elements.  Python Optimization Scripts from nikiml were used
to find the "best" set of dimensions.

Two versions are analyzed here: a) 7-El Wedge LPDA and b) 7-El Layered LPDA, with ALL SAME Dimensions,
except for Separation between Top & Bottom sets of LPDA Elements.

a) 7-El Wedge LPDA:

UHF Raw Gain = 7.9 to 9.0 to 8.1 dBi, F/B & F/R Ratio Min = 22.5 dB and SWR (75-ohms) Under 1.8.

===============================================================
b) 7-El Layered LPDA:

UHF Raw Gain = 7.9 to 9.0 to 7.9 dBi, F/B & F/R Ratio Min = 21.0 dB and SWR (75-ohms) Under 1.9.
[NOTE: More accurate EVAL found only 0.1 dBi less Gain at 698 MHz, see EVAL RESULTS Files.]
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159 Visits
37 Images
Linked Album
holl_ands
The Beat
22. The Beat 
127 Visits
132 Images
Linked Album
hpdramaclub
Woodworking
23. Woodworking 
These are our woodworking projects, beginning in 2012. I'm having so much fun!
538 Visits
65 Images
Linked Album
lindyjo450
Cottesloe Sculpture By the Sea 2015
24. Cottesloe Sculpture By the Sea 2015  (March 2015)

The 11th annual Sculpture by the Sea was held on Cottesloe Beach in March 2015. This is the world's largest annual outdoor sculpture exhibition that is free to the public. With an estimated annual attendance of 215,000 people each year, this massively popular event captures the creativity of over 70 local, interstate and international artists every year, featuring all kinds of conversation-starting and thought-provoking sculptures. These images bring you some of the entries that I was able to capture in fleeting seconds between the crowds of admirers blocking the view.

515 Visits
74 Images
Linked Album
gladysclancy
/hu4baylooprlh410x14norefl
25. /hu4baylooprlh410x14norefl  (21 Mar 2015)
Hi-VHF + UHF 4-Bay (10.125 x 14) + Loop (RLH4) + No Reflector analyzed using 4nec2 after determining Dimensions using nikiml's Python Optimization Scripts.
340 Visits
21 Images
Linked Album
holl_ands
Murder rock/Brick Foam
26. Murder rock/Brick Foam 
245 Visits
3 Images
Linked Album
bloodandwhiskeydesign
UHF Hourglass Loop
27. UHF Hourglass Loop  (30 Nov 2012)
UHF Hourglass Loop analyzed using 4nec2 after finding "best" dimensions using nikiml's Optimizations Scripts.
Based on UHF Hourglass Loop posted by oneolddude in www.digitalhome.ca forum.
However Optimization and Rescaling increased 470 MHz Gain by about 0.5 dB with Max Gain on 698 MHz.

Five versions are analyzed here.  ALL provide very wide Beamwidths (60-50 degrees even at High Freqs):

#############################################
a) AWG6 with NO Reflector Rods (Optimization search across ALL THREE Variables):
UHF Raw Gain = 4.7-6.0 dBi with Excellent SWR under 1.6, using AWG6.

#############################################
b) AWG10 Elements + 1/4" 12x Reflector Rods (Optimization search across ALL THREE Variables):



#############################################
c) AWG6 Elements + 1/4" 15x Reflector Rods (Search across ALL SIX Variables):
UHF Raw Gain = 9.6 to 10.4 to 10.3 dBi, F/B & F/R Minimum = 19.6 dB and  SWR (300-ohms) Under 1.8.

#############################################
d) AWG12 Elements + AWG12 15xReflector Rods:
UHF Raw Gain = 9.4 to 10.2 dBi, F/B & F/R Minimum = 17.1 dB and SWR (300-ohms) Under 1.8.

#############################################
e) Grid Mesh 24x19.5-in (per 300-ohm post):
UHF Raw Gain = 9.4-10.8 dBi with SWR under 2.4, using AWG6.
Front/Back and Front/Rear Ratios 15 dB or better.

#############################################
f) Grid Mesh 24x19.5-in (Re-Optimized using nikiml's Python scripts):
UHF Raw Gain = 9.5-10.6 dBi with SWR under 2.5, using AWG6.
Front/Back and Front/Rear Ratios 17 dB or better.

PS: For improved F/B and F/R Ratios, should try different Grid Mesh sizes.

EDIT (10Dec2012): Added 4nec2 analysis with Grid Mesh (per 300ohm post) and
Re-Optimized version, with somewhat better F/B and F/R Ratios.

EDIT (10Jul2014): Replaced 15xRR version with improved SWR version (with 0.2 drop in Gain).

EDIT (8Mar2015): Added 11RR version.
4168 Visits
81 Images
Linked Album
holl_ands
UHF H2 2-Bay Bowties + Various Refl Rods
28. UHF H2 2-Bay Bowties + Various Refl Rods  (4 Mar 2015)
UHF H2 (10.5x12.25) 2-Bay Bowtie with 11 Reflector Rods analyzed using 4nec2 after determining
dimensions using nikiml's Python Optimization Scripts.

UHF Raw Gain = 11.7 to 13.8 dBi, F/B & F/R Ratio Min. = 18.8 dB and SWR (300-ohms) Under 2.6.
Hi-VHF Raw Gain = 7.9 to 7.8 to 7.9 dBi, F/B & F/R Ratio = 9.8 to 15.6 dB and SWR (300-ohms) = 75 to 24.

OPTIMIZED DIMENSIONS:
BowLength = 10.5-in = Whisker Length,
BowSpacing = 12.25-in = Separation between Bowties,
TineSep = 6.0-in = Tine Separation Tip-to-Tip,
FeedSep = 2.5-in = Feedline Separation,
Element & Feedline Wire Size = AWG10,
Reflector Rod Wire Size = QICT (Quarter-Inch Copper Tubing) [Could be thinner],
RS = 5.0-in = Reflector Rod Separation behind Hourglass,
RR = 2.25-in = Reflector Rod-to-Rod Separation,
YRod = 17.0-in = Reflector Rod Half-Lengths.
278 Visits
21 Images
Linked Album
holl_ands
UHF Quad-Trapezoid-Loop+2xBars
29. UHF Quad-Trapezoid-Loop+2xBars  (11 Jul 2014)
UHF Quad-Trapezoid-Loop+2xBars
UHF Quad-Trapezoid-Loop + 2 Bar Elements analyzed using 4nec2.
Formed by adding outer parts of Chireix 2-Square Antenna to an Hourglass-Loop.
All dimensions determined using nikiml's Optimization Scripts:

Two versions analyzed: Quad-Trap+2xBars (NO Reflector) and Quad-Trap+2xBars (15 RR).

=================================================
a) Quad-Trapezoid-Loop+2xBars (NO Refl): AWG10 Elements.

UHF Raw Gain = 6.6 to 9.4 dBi, SWR (300-ohms) under 1.8 and Beamwidth = 80 to 50-degrees.

=================================================
b) Quad-Trapezoid-Loop+2xBars + 11 Reflector Rods: AWG10 Elements and 1/4-in O.D. Reflector Rods.



=================================================
c) Quad-Trapezoid-Loop+2xBars + 15 Reflector Rods: AWG10 Elements and 1/4-in O.D. Reflector Rods.

UHF Raw Gain = 11.4 to 12.6 to 11.1 dBi, F/B & F/R Ratio Min = 18.1 dB and SWR (300-ohms) under 2.5.
Note 60-50 degree Beamwidth and EXTREMELY DEEP 64+ dB Notch directly to Rear.
5331 Visits
51 Images
Linked Album
holl_ands
UHF "Figure-8" Twin-Loops + 11RR - OPT
30. UHF "Figure-8" Twin-Loops + 11RR - OPT  (6 Mar 2015)
UHF "Figure-8" Twin-Loops + 11 Reflector Rods analyzed using 4nec2 after determining
dimensions using nikiml's Python Optimization Scripts.

UHF Raw Gain = 9.7 to 10.9 dBi, F/B & F/R Ratio Min. = 18.1 dB and SWR (300-ohms) Under 2.2.
306 Visits
21 Images
Linked Album
holl_ands
 
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