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 Public Gallery | Home > Arts and Crafts Prev 15 | Next 15 
Arts and Crafts
16 - 30 of 674 Total. Shared
Mana series 2016
16. Mana series 2016 
20550 Visits
6 Images
Linked Album
17. 2016 
Included here are Digital Extra pages produced by Mr. Beckett in 2016. In addition to design, Mr. Beckett tracks and supervises production of Tech Extra and Travel Extra.
24471 Visits
174 Images
Linked Album
18. cards 
Home made cards, personalised candles and other home made nick knacks.
12861 Visits
14 Images
Linked Album
Vintage Jools Take 2
19. Vintage Jools Take 2 
11582 Visits
66 Images
Linked Album
20. Performing arts center 
5 Visits
0 Images
Linked Album
21. Country drive 4 
6 Visits
0 Images
Linked Album
Antennacraft G-1483 Hoverman Type 2
22. Antennacraft G-1483 Hoverman Type 2  (4 Apr 2013)
Antennacraft G-1483 variation of (SBGH) Hoverman Type 2 (With 4 Reflector Rods) analyzed using 4nec2.

Dimensions per EscapeVelocity, 4nec2 file by <300ohm> as modified by holl_ands: added FR & RP Cards
to facilitate repeatable runs.
14699 Visits
15 Images
Linked Album
Rocking chair
23. Rocking chair  
10710 Visits
2 Images
Linked Album
Army boots
24. Army boots 
11646 Visits
3 Images
Linked Album
UHF HD Horizon X10 Two Slot Antenna
25. UHF HD Horizon X10 Two Slot Antenna  (7 Nov 2015)
UHF HD Horizon X10 Two Unequal Slot Antenna from Solid Signal analyzed using 4nec2.  Dimensions derived from a posted
Photo of the Front Panel (compared to Mfr's HxW) and (since a measurement was not available) performance was
calculated for THREE values for Reflector Separation from Front Panel....which is NOT critical for 3.5 to 4.5-inches.
10882 Visits
19 Images
Linked Album
26. Bj 
Hope u Will enjoy it <3
12570 Visits
2 Images
Linked Album
27. cm4228hdnoreflHHH  (20 Oct 2015)
CM4228HD with NO Reflector and HHH (Holl_ands Horizontal Harness) analyzed using 4nec2, SAME version as OPTIMIZED earlier with 16 Reflector Rods.

UHF Raw Gain = 11.7 to 13.8 dBi, F/B & F/R Ratio = 1.7 to 0.5 dB and SWR (300-ohms) = 2.8 (Good).
Hi-VHF Raw Gain = 3.5 to 5.0 dBi, F/B & F/R Ratio = 1.2 to 1.0 dB and SWR (300-ohms) = 3.3 to 4.0 (a bit High).
10363 Visits
21 Images
Linked Album
Hi-VHF Vertical Folded Dipole OMNI
28. Hi-VHF Vertical Folded Dipole OMNI  (29Oct2015)
Hi-VHF Vertical Folded Dipole analyzed using 4nec2.  It provides a TRUE OMNI-Directional Azimuthal Pattern.

Fol. analysis assumed fol. Dimensions:
L2=27.5          ' Folded Dipole Overall Element Length
FW=2.0           ' Distance between Folded Dipole Elements
RACT=0.2845  ' Radius (inches) for Driven Element is Standard Type M 1/2-in O.D. Copper Tubing

Dimensions for other Diameter Tubing can be found in Analysis of Hi-VHF Folded Dipole for Horizontal Polarized signals:
4531 Visits
9 Images
Linked Album
UHF FF3 3-Bay Bowtie - NO Reflector
29. UHF FF3 3-Bay Bowtie - NO Reflector  (21 Oct 2015)
UHF Free-Form 3-Bay (FF3) analyzed using 4nec2 after determining Dimensions using
nikiml's Python Optimization scripts.

Three alternative interconnection Topographies were determined to be of interest for further
investigation (starting with the BEST).  Nearly ALL Bowtie Parameters were allowed to be
INDEPENDENTLY varied in determining the fol. three versions of the FF3 (Free-Form 3-Bay Bowtie):

Note that Gain Charts are for TOTAL (Horiz. + Vert.) Gain.  Azimuthal Charts show that
there is lower, but significant Vertical Gain to the SIDES of the Antenna.

a) Remove Top Bowtie from FF4 (so Offset Feedpoint) and Re-Optimize:

UHF Raw Gain = 8.6 to 11.4 dBi and SWR (300-ohms) Under 2.7 is Good.
Hi-VHF Raw Gain = 2.4 to 3.0 dBi and SWR (300-ohms) = 3.9 to 6.3 is Higher than Desired.

b) Move Feedpoint to Inner Bowtie with Crossover Feedlines to each Outer Bowtie, which
are presumably needed to ensure all three signals are In-Phase at the Feedpoint:

UHF Raw Gain = 8.1 to 10.1 dBi and SWR (300-ohms) Under 2.6 is Good.
Hi-VHF Raw Gain = 2.6 to 2.9 dBi and SWR (300-ohms) = 9.4 to 2.1 is Excessive on Ch7-11.

c) Offset Feedpoint (like a), but with Straight (NO Crossover) Feedlines to each Outer Bowtie:

UHF Raw Gain = 7.1 to 9.4 to 9.1 to 10.7 dBi and SWR (300-ohms) Under 3.1 is a Bit Higher then Desired.
Hi-VHF Raw Gain = 2.1 to 2.6 dBi and SWR (300-ohms) = 7.8 to 6.4
is Excessive.
1787 Visits
87 Images
Linked Album
UHF M3 3-Bay Bowtie - NO Reflector
30. UHF M3 3-Bay Bowtie - NO Reflector  (20 Oct 2013)
UHF 3-Bay Bowtie [aka M3 (9.5x9.0)] with NO Reflector analyzed using 4nec2.
Height=21-inches, Width=20-inches.

One Bowtie on the M4 (9.5x9.0) 4-Bay Bowtie Antenna was removed to determine the performance of a SHORTER 3-Bay version.
The TOP rather than the BOTTOM Bowtie was removed since it results in a slightly UPWARD tilt (5-10 deg) in the Elevation Pattern in UHF Band.

Raw Gain in the Hi-VHF Band on all but the lowest channels was severely affected as the Gain Pattern shifted to the OVERHEAD direction.
3922 Visits
39 Images
Linked Album
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