• Main Page
 • Home
• Antennas
 • 432 MHz
 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 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
Stacking
Matching
YBN 705m 5 Element Yagi with Conventional Driver
This little Yagi has a high F/B, which makes it quite useful as a contest stack.
The YBN 705m is the very pilot model which was used to derive all the "OnBoomBCFactors" from
(see Dubus 1/2011). It has been measured about 40 times using various boom dimensions and element
lengths. That is why I do quite an excurse about NEC model segmentations down the page.
If you want to build one ...
just pick a building style, element diameter and boom dimension.
The given full lengths are 'ready to build' measures.
The photo below shows the measurementYagi on PPplastic boom. See the symmetrising 3/4 λ coax line
connected to "gnd" using an nbushing screwed to the provisional aluminium subboom to mount the PPYagi to the mast?
and with 5 mm elements & SM7DTT holders on 20 x 20 mm boom
• A lightweight YBN 705m built by Kazuo, 7L1TIG  using a sheet metal strip 2 x 10 mm as dipole arms
Photos: Kazuo, 7L1TIG
More about the YBN 705m with sheet metal dipole incl. VSWR & Return Loss plots on 7L1TIG's website
This website is in Japanese language. Use a free website online translator.
A YBN705m for testing BC by Jozef, HA1VQ
Boom is 35 mm round aluminium tube
Element insulators are HA1KYY made
Performance Data
ele. 6 mm
Gain vs. isotr. Rad. 10.3 dBi
Gain vs. Dipole 8.2 dBD
3 dB Eplane 53.4 deg.
3 dB Hplane 69.8 deg.
F/B 24.2 dB
F/R 21.9 dB
Impedance 50/200 ohms
Mechan. Length 480 mm
Electr. Length 0.69 λ
Stacking Dist. hpol.
toptobottom 0.61 m
sidebyside 0.77 m
Geometry
<= 6 mm ele. semiinsulated
mounting on boom, screw upside down with M3 thread in element (as per DJ3JJ, s. Dubus 1/2010)
 Plastic Boom & Insulators   Full Free Space   Boom 15x15 mm   Boom 20x20 mm   Boom 25x25 mm 
Pos. 1/2 Length Segm. 1/2 Length Auto Segm. Full Lgth +4.8 Full Lgth +7.5 Full Lgth +11.5
in NEC in NEC
Refl. 0 168.000 11 168.125 10 340.80 343.75 347.50
DE 91 161.500 11 161.625 11 327.80 330.75 334.50
D1 133 155.750 11 155.875 9 316.30 319.25 323.00
D2 266 151.250 10 151.375 9 307.30 310.25 314.00
D3 480 138.500 9 138.625 8 281.80 284.75 288.50
ele. 6 mm ele. 6 mm ele. 6 mm ele. 6 mm ele. 6 mm
The Drivers diameter is 10 mm for all examples.
"Ready to saw and drill" data for mounting elements on boom with standard insulators on 20 x 20 mm boom including a 30 mm offset from booms end:
The segmentation used for the plastic boom reference Yagi model is auto segmentation at 500 MHz.
Same was used on longer builds (YU7EF EF7015 +27 Yagis) with good results. Note that the delta length
between Auto Segmentation at 432.1 MHz and 500 MHz is covered by adapting element lengths by 0.25 mm only.
The  Plastic Boom & Insulators  element lengths are what I have published in my article on 432 MHz
OnBoomBC in Dubus 1/2011. Now why are there two segmentations given? Because for measuring the
set of BC numbers and following real builds we have used the plastic standard insulators throughout.
From first measurment on the plastic boom Yagi to real builds. They made a constant offset which is
handled fitting the NEC models with that little higher segmentation base. See the exellent compliance
between simulation and real plot of the PPboom Yagi below.
Other diameters and building lengths
 Plastic Boom & Insulators   Full Free Space   Boom 15x15 mm   Boom 20x20 mm   Boom 25x25 mm 
Pos. 1/2 Length Segm. 1/2 Length Auto Segm. Full Length Full Length Full Length
in NEC in NEC
Refl. 0 166.000 11 166.125 10 16x.00 16x.00 16x.00
DE 91 161.500 11 161.625 11 16x.00 16x.00 16x.00
D1 133 153.970 11 154.095 9 16x.00 16x.00 16x.00
D2 266 149.200 10 149.325 9 16x.00 16x.00 16x.00
D3 480 136.100 9 136.225 8 16x.00 16x.00 16x.00
ele. 8 mm ele. 8 mm ele. 8 mm ele. 8 mm ele. 8 mm
 Plastic Boom & Insulators   Full Free Space   Boom 15x15 mm   Boom 20x20 mm   Boom 25x25 mm 
Pos. 1/2 Length Segm. 1/2 Length Auto Segm. Full Length Full Length Full Length
in NEC in NEC
Refl. 0 164.700 11 164.820 10 16x.00 16x.00 16x.00
DE 91 161.500 11 161.620 11 16x.00 16x.00 16x.00
D1 133 152.600 11 152.720 9 16x.00 16x.00 16x.00
D2 266 147.300 10 147.420 9 16x.00 16x.00 16x.00
D3 480 134.700 9 134.820 8 16x.00 16x.00 16x.00
ele. 10 mm ele. 10 mm ele. 10 mm ele. 10 mm ele. 10 mm
The Drivers diameter is 10 mm for all examples.
• "Ready to saw and drill" data for mounting 4.0 mm elements insulated through boom with SM5BSZ's BC.exe applied
Note that with an elements insulated through boom built for best results boomlength and positions to first /last element must be kept as given.
Because the position of an element relative to its nearer boom end is a serious parameter in the BC.exe.
This table is only valid for:
Boom shape: square
Boom dim: 20 x 20 mm
Wall thickn.: 2.0 mm
Holes in boom: 6.0 mm
Offset rear: 40 mm
Offset front: 40 mm
• Data set for 4 mm elements with rear & front boom end offset = 40 mm
• Data set for 4 mm elements with rear boom end offset = 300 mm for formast mounting
• "Ready to saw and drill" data for mounting 3/16 in (4.76) mm elements insulated through boom with SM5BSZ's BC.exe applied
Note that with an elements insulated through boom built for best results boomlength and positions to first /last element must be kept as given.
Because the position of an element relative to its nearer boom end is a serious parameter in the BC.exe.
This table is only valid for:
Boom shape: square
Boom dim: 20 x 20 mm
Wall thickn.: 2.0 mm
Holes in boom: 7.5 mm
Offset rear: 300 mm
Offset front: 40 mm
• Data set for 3/16 in elements with rear boom end offset = 300 mm for formast mounting
This table is only valid for:
Boom shape: square
Boom dim: 5/8 x 5/8 in
Wall thickn.: 1.6 mm
Holes in boom: 7.5 mm
Offset rear: 300 mm
Offset front: 40 mm
• Data set for 3/16 in elements with rear boom end offset = 300 mm for formast mounting
Pattern and VSWR Plots
Current distribution
Elevation plot at 432.1 MHz
Azimuth plot at 432.1 MHz
RL and SWR plot with 4nec2
Comparison of simulated and measured Return Loss
Mind that this is on 70 cm Band ... have you seen closer plots of Return Loss by other designers here ever?
There is nothing "trimmed" for best SWR here. The chart shows the PPboom Yagis without any BC.
This is a measurement "out of the box" with Element lengths trimmed to the 10th of a millimeter
with a large calliper gauge and carefully trimmed and measured symmetrising coax line. This is
yet another confirmation for a low segmentation density close to auto segmetation being much
closer to real world dimensions then often proclamated 30+ segments per wire if it is about a
standard Yagi with a dipole.
Read more about building this Yagi in my Article 'Applied Conversion of Segmented Wires from NEC to 432 MHz Yagi Elements' in Dubus 1/11
Stacking
here is a proposal how to stack for very high F/B using geometrical shift of the Yagis by 1/4 λ in beam direction.
Stacking distance is 700 mm per Yagi  the whole stack is 5.2 m in height then. This stacking scheme helps to boost
the F/B. It goes back on the S53WW4, a 4 Yagi stack by Roby, S53WW (http://lea.hamradio.si/~s53ww/s53ww4/s53ww4.htm)
The Yagis are fed with individual coax lengths from the splitter on. The geometrical shift must be compensated by longer
coax feed lines. A forward bound shift by a 1/4 λ must be encountered by an extra 1/4 λ added to this Yagis feed line
So that it is acutally fed with a phase lag of 90 degrees. Double that for the next Yagis with 2 x 1/4 λ and same scheme
i.e. 3 x 1/4 λ = 270 deg. for the inner pair of Yagis. Mind the real vfactor of your coax and measure lengths exactly please.
Elevation plot with lowest Yagi at 2.6 m over perfect ground
F/B ratio for this configuration is 38 dB at a HBW of 53.2 deg. and gain of 19.58 dBi in free space
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 right length instead of refering to given vfactors 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

