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Arts and Crafts
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MCSQG  january
16. MCSQG  january  (11/18)
I seen a different way of doing the trapunto. It is easier and faster but you will not see the effect until it is quilted.
199 Visits
6 Images
Linked Album
HP Drama Club Ten Year Anniversary
17. HP Drama Club Ten Year Anniversary  (November 10, 2014)
425 Visits
135 Images
Linked Album
MCSQG February
18. MCSQG February   (11/1/14)
Block of the month for February
techniques appliqué, chenille (optional)
172 Visits
7 Images
Linked Album
Quilt show 2013
19. Quilt show 2013  (2013)
Bloomington quilt show
160 Visits
26 Images
Linked Album
UHF CM4221HD (Hacked) - No Reflector
20. UHF CM4221HD (Hacked) - No Reflector  (18 Oct 2013)
UHF CM4221HD (Hacked) and NO Reflector analyzed using 4nec2.

CM4221HD measurements per fol. smpowell55 posts:

UHF Raw Gain = 7.4 to 12.2 dBi and SWR (300-ohms) under 2.6.
Hi-VHF Raw Gain = 4.1 to 4.2 dBi and SWR (300-ohms) = 17 to 1.1.
SWR on Ch7-10 degrades Net Gain & EVM (Error Vector Magnitude), but may be adequate for strong stations.
NOTE: As-shipped PCB Balun KILLS VHF.  Above Hi-VHF performance presumes replace with
conventional Transformer (Cylindrical) Balun.

BowLength = 7.9-in, Inner-Inner Bowtie Spacing = 9.84-in, Outer-Inner Bowtie Spacing = 8.46-in,
Tine Separation = 3.94-in.  Feedline Separation = 1.18-in, with 0.8-in at Crossover (2" from Outer Bowtie).
16 Rod Reflectors: 23.6" Long with 1.93" Spacings for Total Height = 30-in.  Separation from Bowties = 4.25-in.

It is presumed that anyone interested enough to view this webpage will
implement the "Hacked Balun" modifications per photo in fol. rabbit73 post
(flip over the Feedlines going into the Balun plus an additional offset):
1538 Visits
21 Images
Linked Album
UHF 21El Curtain Array - NO Refl
21. UHF 21El Curtain Array - NO Refl  (20 Oct 2014)
UHF 21-Element Curtain Array (NO Reflector) analyzed using 4nec2 after RESCALING Wi-Fi version posted by Ross Anderson, W1HBQ.  Also corrected AGT=1.0 after fixing SOURCE Wire Statement error.
631 Visits
13 Images
Linked Album
22. horizstackff4dblanglerefl+HHH  (17 Oct 2014)
Horiz-Stack FF4 + DoubleAngleRefl + HHH
UHF+Hi-VHF HFF8, a Horizontal Stack of 2 ea Free-Form 4-Bays (FF4) with Double Angle Reflectors
(each 48" H x 36" W using 2x2-in Grid) and HHH (Hollands Horizontal Harness) were analyzed using 4nec2.
Essentially all Dimensions were determined using nikiml's Python Optimization Scripts.

Performance was slightly "Better" at THREE notable Stacking Distances:
34.821-inches (NO GAP, Continuous Reflector), 35-inches (Metal-to-Metal about 1/4-inch)
and 51-inches, which are analyzed below.
There were notable Stacking Distances further out, but none were particularly "Better".

Although the differences are only a few tenths of a dB, Stack Distance = 51-inches was just
a bit "Better", esp. Hi-VHF, than at 35-inches.  The wider Separation may also be slightly
"Better" at combating Multipath Fading due to the reduction in Statistical Correlation
between the two Antenna signals.  The "NO GAP between Reflector" alternative was slightly worse.

a) Horizontal Stacking Distance (4-Bay Center-to-Center) = 34.821 inches (NO GAP between Reflectors).


b) Horizontal Stacking Distance (4-Bay Center-to-Center) = 35-inches (0.18-in GAP between Reflectors).

c) Horizontal Stacking Distance (4-Bay Center-to-Center) = 51-inches (16.18-in GAP between Reflectors).
126 Visits
42 Images
Linked Album
Joanne's Cookies
23. Joanne's Cookies  (October 16, 2014)
115 Visits
22 Images
Linked Album
24. UHF Batwing - No & 11RR  (16 Oct 2014)
UHF Batwing Antenna with No Reflector and 11 Reflector Rod Screen analyzed using 4nec2.  Based on 4nec2 files provided by user <300ohm>.
0 Visits
0 Images
Linked Album
UHF 4-Square Chireix Free Form
25. UHF 4-Square Chireix Free Form  (15 Oct 2014)
4-Square Chireix Free Form (Unequal Inner/Outer Lengths & Angles) Antenna with NO Reflector and 11 Reflector Rods analyzed using 4nec2.
574 Visits
27 Images
Linked Album
Displaying Copper Roses
26. Displaying Copper Roses   (October 2014)
My Copper Roses often are given as Wedding gifts,  7th Anniversary, Christmas, Valentine's Day, Mothers' Day, and Birthdays and as symbols of affection.
These patrons have sent me photos of my copper roses in situ.
6795 Visits
48 Images
Linked Album
27. MCSQG   (10/1/14)
January BOM.
Theme:  calendar quilt
Techniques:  Applique, padded appliqué, hand or machine embroidery
403 Visits
16 Images
Linked Album
HIVHF+UHF VEE Folded Dipole
28. HIVHF+UHF VEE Folded Dipole  (25 Sept 2014)
Hi-VHF+UHF "VEE" Folded Dipole analyzed using 4nec2.
1375 Visits
27 Images
Linked Album
VHF Simple-VEE-Rabbit-Ears
29. VHF Simple-VEE-Rabbit-Ears  (14 Feb 2011)
VHF Simple-VEE-Rabbit-Ears (no matching network) analyzed using 4nec2.

Hi-VHF Band Optimum Whisker Length = 14.75 for Quarter-Inch-Copper-Tubing (QICT) with Feedpoint Gap = 0.75-in.

For 45-degree Angle, Horizontal Polarization Gain was equal to Vertical Polarization Gain across the Hi-VHF Band.

Note: Even a 0.5-inch error in adjusting lengths of Rabbit Ears severely degraded SWR, although only minor impact on Raw Gain.

EDIT (10Sep2011): Added a "What-IF" exercise to illustrate the Raw Gain and SWR (if 300-ohms) from Ch2-13.
Note that SWR in Hi-VHF Band is four time higher than for 75-ohms, and becomes even more excessive on lower freqs,
as the Impedance becomes nearly all Capacitance (negative Reactance).

EDIT (16Jan2012): Added Circular Polarization Azimuthal Plots.  Note that Right Circular = Left Circular at 90-deg & 270-deg Azimuths, so there is very little suppression of Cross-Polarized (e.g. reflected Multipath) signals.

ERRATA (5Sep2014): Uploaded revised 4nec2 File with sin and cos functions reversed to match Angle Definition in Comment description.  Since all charts were for 45-degree Angle, they are NOT affected.
977 Visits
24 Images
Linked Album
UHF Vert 8-Bay Dipole + 43 Pair RR - OPT
30. UHF Vert 8-Bay Dipole + 43 Pair RR - OPT  (1 Sep 2014)
UHF Vertical 8-Bay FAT Dipole with 43 Pairs of Reflector Rods analyzed using 4nec2 after
determining Dimensions using nikiml's Optimization Scripts.
760 Visits
15 Images
Linked Album
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