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 YBN 705m
A 0.5 m 432 MHz blue print of the YBN 25m 50 ohms
high F/B direct feed 144 MHz Low Noise Yagi 3D Plot
 YBN 708z
A 1.5 m high gain 28 ohms Yagi. A design partly based on the hardware of the WY7010,
turning it into a 8 ele. 28 ohms Yagi with cleaner pattern, +1.8 dB gain and better VSWR. Azimuth Plot
 YBN 7014wz
Tune up your 19 ele. Tonna!A design based on the hardware of the F9FT,
turning it into a 14 ele. OWL with cleaner pattern, +0.3 dB gain and SWR less than 1.2 from 430 to 440 MHz Azimuth Plot
 GTV 702w
A 0.14 m GTV useful for portable operation and up to the satellit band
and handheld activities of any kind Elevation Plot
 GTV 703w
A 0.21 m GTV useful for portable operation and up to the satellit band
and lower noise stacks of any kind Elevation Plot
 GTV 704m
A 0.34 m GTV useful for portable operation up to the satellit band
and lower noise stacks of any kind Elevation Plot
 GTV 707w
A 0.96 m GTV useful for portable operation up to the satellit band
and lower noise stacks of any kind Elevation Plot
 GTV 707n
A 1.1 m 432 MHz blue print of the low impedance, yet 50 ohms
direct feed 144 MHz Low Noise Yagi introduced in Dubus 1/2013 Elevation Plot
 GTV 708n
A 1.3 m 432 MHz GTV with high gain but low backlobe volume. Makes
a very compact 4 Yagi bay for QRP EME or contesting.
Elevation Plot
 GTV 709w
A 1.44 m GTV ment to be useful as a vertical stack for contesting
or be an ideal small size portable Yagi Elevation Plot
 GTV 7010w
A 1.63 m GTV useful for portable operation up to the satellit band
and lower noise stacks of any kind Elevation Plot
 GTV 7011w
A 2.01 m GTV ment to be useful as a vertical stack for contesting
or be an ideal small size portable Yagi or minimum size EME 4 bay Elevation Plot
 GTV 7013m
A 2.5 m GTV ment to be useful as a vertical stack for contesting
or be an ideal small size portable Yagi or minimum size EME 4 bay Elevation Plot
 GTV 7014m
2.9 m version of the low impedance, yet 50 ohms
direct feed Low Noise Yagi with bent DE introduced in Dubus 1/2013 Elevation Plot
 GTV 7017m
3.7 m version of the low impedance, yet 50 ohms
direct feed Low Noise Yagi with bent DE introduced in Dubus 1/2013 Elevation Plot
 GTV 7019m
4.2 m version of the low impedance, yet 50 ohms
direct feed Low Noise Yagi with bent DE introduced in Dubus 1/2013 Elevation Plot
 GTV 7021n
4.7 m version of the low impedance, yet 50 ohms
direct feed Low Noise Yagi with bent DE introduced in Dubus 1/2013 Elevation Plot
 GTV 7023m
5.3 m version of the low impedance, yet 50 ohms
direct feed Low Noise Yagi with bent DE introduced in Dubus 1/2013 Elevation Plot
 GTV 7025m
5.9 m version of the low impedance, yet 50 ohms
direct feed Low Noise Yagi with bent DE introduced in Dubus 1/2013 Elevation Plot
 GTV 7030m
7.3 m version of the low impedance, yet 50 ohms
direct feed Low Noise Yagi with bent DE introduced in Dubus 1/2013 Elevation Plot
 GTV 7034w
8.5 m version of the low impedance, yet 50 ohms
direct feed Low Noise Yagi with bent DE introduced in Dubus 1/2013 Elevation Plot
 GTV 7046w
12.0 m version of the low impedance, yet 50 ohms
direct feed Low Noise Yagi with bent DE introduced in Dubus 1/2013 Elevation Plot

....... 
Performance Data and Geometry
Pattern and VSWR
Download as File
Stacking
Diamond Stagger Stacking Crossover
Matching
GTV 708n Yagi with bent Driven Element
EME + SSB narrow bandwidth version ... strictly G/T breeding
This Yagi has very low back lobes for its length. It may serve as single antenna for portable
use and certainly make a useful 4 x vertical stack. It makes a quiet contest antenna due to its
high F/B. The bent DE (K6STI style) transforms from approx. 17 ohms to 50 ohms at feed point.
The GTV 708n is EME tested
GTV 708n built by Kazuo, 7L1TIG, see his website for details
VSWR plot: Note  7L1TIG scaled this Yagi to 430 MHz for use in JA FM band
Images: with kind permission of Kazuo, 7L1TIG
GTV 708n built by Maxime, F4FEY
And VSWR (ROS) plotted on his AAI Vector Impedance Analyzer N1201SA
Images: on courtesy of Maxime, F4FEY
GTV 708n built and tested as EME proof in ARI contest by Thomas, M0ABA
This yagi is built on a 58 inch boom with 4 mm elements using 7arrays through boom insulators.
And now here is screen shot of using the GTV 708n for all the smart critics that say 'ah ... thats just tropo':
NC1I (which is based stateside guys) received B14 dB by MX0CNS (thats now in Europe guys).
And a WSJT screenshot by Thomas listening to QSO DL7APV  IK0IXO:
he reports very little noise (hence Low Noise Yagi ...), see the clean SpecJT screen. Mind this is EME
signal reception with a single small Yagi in daytime, with an ordinary preamp only.
Current distribution
3D Pattern
Performance Data
Specs: with 4 mm elements @ 432.1 MHz
Gain vs. isotr. Rad. 13.6 dBi (13.62 dBi with 8 mm ele.)
Gain vs. Dipole 11.5 dBD
3 dB Eplane 38.8 deg.
3 dB Hplane 44.0 deg.
F/B 24.9 dB
F/R 27.9 dB
Impedance 50 ohms
Mechan. Length 1334 mm incl. 2 x 30 mm stand off
Electr. Length 1.84 λ
Stacking dist. hpol.
toptobottom 0.93 m or 3.04 ft
sidebyside 1.04 m or 3.43 ft
How many OMs have been looking up this design?
Geometry
Table 1: GTV 708n, 8 mm elements on boom:
Dimensions using onboom holders and BC acc. DG7YBN
Refl DE D1 D2 D3 D4 D5 D6
Pos. 0 92 154.5 289 504 768 1034 1274
Ele. 330.3 (301.6) 306.4 298.7 288.8 280.8 274.4 263.3 <= ex. SBC and BC
Diam. 8 10 8 8 8 8 8 8
Total BC is SBC = 1.28 mm plus one of the following BC numbers
Standard Holders* 15 mm: 4.8 mm (*) as sold by Konni, WiMo, Nuxcom, (7arrays 20 mm)
Standard Holders 20 mm: 7.5 mm
Standard Holders 25 mm: 11.5 mm
7arrays Holders 25 mm: 7.1 mm
Table 2: GTV 708n, 4 mm elements through boom:
"Ready to saw and drill" data for mounting elements through boom with BC according SM5BSZ's BC.exe:
Note: with through Boom BC it is important to stick to the boom end offsets given below!
Metric Boom 20 x 20 x 2 mm
Boom shape: square
Boom dim: 20 x 20 mm
Wall thickn.: 2.0 mm
Holes in boom: 6.0 mm
Offset rear: 300 mm
Offset front: 40 mm



Note: with through Boom BC it is important to stick to the boom end offsets given below!
With 300 mm offset on rear boom end for effective formast mounting
Imperial Boom 58"
Boom shape: square
Boom dim: 5/8 x 5/8 inch
Wall thickn.: 1.6 mm
Holes in boom: 6.0 mm
Offset rear: 300 mm
Offset front: 40 mm



Note:
All the above include a "Segmentation Density Correction" (SBC) of 1.28 mm plus an offset of 0.70 mm per element = 1.98 mm
for compensation of the insulators (7arrays.com ) as shown above in combination with SM5BSZ'S BC.exe values.
Note: with through Boom BC it is important to stick to the boom end offsets given below!
Read abt. the SBC here .
Same with 300 mm offset on rear boom end for effective formast mounting
In the download section you find a CSV file for the Yagi Element Configuration Tool of this Yagi with 4 mm elements
with you can use for own adaptions to variations of boom dimensions etc.
For making of a 'Blade Dipole' which I recommend for elements through boom builds
Sketch of Bent Dipole
Radiation Pattern and VSWR Plots
Elevation and Azimuth plot at 432.1 MHz (4 mm ele.)
SWR and Return Loss plots  simulated with 4nec2
(I have settled the best Retrun Loss a bit higher for giving headroom in wet weather)
Gain, F/B and F/R 431 to 434 MHz
Downloads
EZNEC file of this Yagi with Ø 4 mm ele.
EZNEC file of a 4 Yagi Bay with Ø 4 mm ele.
EZNEC file of this Yagi with Ø 8 mm ele.
CSV file of this Yagi with Ø 4 mm ele. for the BCExcel
Stacking
As on 432 MHz the Yfactor = T_earth / T_sky is so high, I see little chances to
improve an array's RX performance by using "Over Stacking" distances. However, depending on
the level of local QRM it might be worthwhile to try a decreased distance, especially in the Hplane.
Stacking Dist. DL6WU Formula
Hplane 1.04 m
Eplane 0.93 m
A 4 Yagi bay
Elev. Plot
Az. Plot
Gain vs. isotr. Rad. 19.53 dBi
Gain vs. Dipole 17.38 dBD
3 dB Hplane, appr. 17.4 deg.
3 dB Eplane, appr. 19.8 deg.
F/B 28.9 dB
F/R 26.0 dB
T_ant 41.9 K
G/T 3.30 dB
3D pattern plot with 4nec2's 3D viewer
A Crossover between Diamond and Stagger Stacking
This stacking scheme is performed at stacking at DL6WU Distances plus 40 Percent
for both E and H plane.
Due to the larger stacking distances and hence a larger effective Aperture Area Diamond Stacking results in higher gain
at more modest side lobes with same Aperture Area used with the classical stacking scheme. However the rear lobes
grow as gain grows. I added Stagger Stacking as a proven tool to reduce the amount of rear lobes for arrays
formed of small Yagis.
Note that the mid pair of Yagis must be feed with a phase lag of 90 degrees by using
feedlines that are 0.25 wave length longer than the ones for the upper and lower Yagi.
Stacking Dist. DL6WU Formula x 1.40
Hplane 1.46 m
Eplane 1.30 m
mid Yagis in x 171 mm
Find a link to more information about Stagger Stacking down the page.
Attenzione! 
Viewing and judging Patterns of Diamond Stacks by Azimuth and Elevation Plots leads to wrong conclusions
according their amount of front, side and rear lobes suppression. As the Diamond Stackings wave interference
pattern runs the most characteristic lobes by a 45 degree shift to the ordinary stacking scheme. So they do not show
in the ordinary Azimuth and Elevation plots. Which is the reason why
many rumors about the marvels of Diamond Stacking are to be heared. Hence I show a 3D plot here.

The above is the reason why I implemented Stagger Stacking into the Diamond Stacking, as that usually
decreases rear lobes by a signifcant amount. And so it does in practise here.
Antenna Temperature and G/T produced with beta version of AGTC by F5FOD
The AGTC (Antenna G/T Calculator) is a shared development of F5FOD and myself, DG7YBN, that will be available
with full open source code. Background of the AGTC is scheduled to be published in Dubus 1/2017
Antenna Temperature and G/T produced with TANT
Read more about Stagger Stacking and feeding such arrays here
Symmetrising 50 to 50 ohms feedline to 432 MHz Bent DE
The principle is similar to the 1/4 Lambda coax. Adding 2 x 1/4 Lambda or a half wave line does not change anything but allows
to form a gentle bow below the boom or until behind the Reflector. Follow practical construction hints on "Building a Yagi" page.
Attenzione!
Take care when lengthening the coax, measure the actual electrical length instead of considering vfactors specified in a catalogue only.
A good choice may be the diam. 5 mm PTFE coax RG142 B/U: real resonate length (432.2 MHz as 3/4 Lambda) shieldshield is around 348 mm
Find more information on Phasing & Matching Lines page
73, Hartmut, DG7YBN

