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Performance Data and Geometry
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Pattern and VSWR
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Download as File
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Stacking
GTV 2-7w Yagi with bent Driven Element
For the given bandwidth this Yagi shows quite a low Antenna Temperature and a moderate gain for its length.
The bent DE (K6STI style) transforms to 50 ohms at feed point for direct feed. Design date of issue: 2020.09.18
GTV 2-7w xpol built by_ZS6JON
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GTV 2-7w 3D pattern plot at 144,3 MHz
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Performance Data
Specs: with 8 mm elements @ 144.1 MHz
Gain vs. isotr. Rad. 12.3 dBi
Gain vs. Dipole 10.1 dBD
-3 dB E-plane 44.6 deg.
-3 dB H-plane 52.8 deg.
F/B -25.0 dB
F/R -22.1 dB
Impedance 50 ohms
VSWR Band Width 1.01:1 *
Mechan. Length 2691 mm
Electr. Length 1.29 λ
Stacking Dist. h-pol. (144.1 MHz)
top-to-bottom 2.34 m or 7.7 ft
side-by-side 2.74 m or 9.0 ft
Stacking Dist. h-pol. (145.5 MHz)
top-to-bottom 2.32 m or 7.6 ft
side-by-side 2.71 m or 8.9 ft
*) as in VE7BQH G/T table = at 145.00 MHz
How many VHF operators have been looking up this design since Sept 2020?
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Geometry
This Yagi with 8 mm elements on a 20 x 20 mm boom with standard insulators
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Ele. 8.0 mm
DE 10 mm
Boom 20 x 20 mm
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"Ready to saw and drill" data for mounting elements on boom with BC according DG7YBN for standard insulators as sold by WiMo, Tino's Funkshop, HF-Kits NL, 7arrays:
Includes an SBC of 1.17 mm
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SegmentationBC = +1.17 mm = (144.3 MHz - 144.5 MHz) * 5.85 mm/MHz
BaseBC (20x20) = +3.90 mm for semi-insulated on boom
Total = +5.07 mm
Note: element lengths for Ø 8 mm fit 5/16" too
The Drivers diameter is 10 mm for all examples.
The EZNEC model is done with Auto-Segmentation at 400 MHz
Ø 3/16 inch Elements, 3/8 inch Dipole - Through Boom - Dimensions (BC acc. SM5BSZ's BC.exe)
Imperial Boom 1"
This table is only valid for:
Boom shape: square
Boom dim: 1 x 1 inch
Wall thickn.: 1.6 mm
Holes in boom: 7.7 mm
Offset rear: 40 mm
Offset front: 40 mm
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Note:
All the above include a "Segmentation Density Correction" (SBC) of 1.17 mm per element.
Note: with through Boom BC it is important to stick to the boom end offsets given below!
Read abt. the SBC here
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Sketch of Bent Dipole
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Pattern and VSWR Plots
Elevation and Azimuth plot at 144.1 MHz
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Elevation and Azimuth plot at 144.5 MHz
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Elevation and Azimuth plot at 145.0 MHz
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Elevation and Azimuth plot at 146.0 MHz
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Finally: A comparison between elevation patterns DK7ZB "7-El.-Ultra-Wideband-Yagi 50 Ohm, 6 MHz SWR < 1,15" and shorter GTV 2-7w.
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RL and SWR plots - simulated
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Gain and F/B, F/R
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Return Loss (dB) plotted on the full xpol, both planed combined by ZS6JON, span 120 - 171 MHz:
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Downloads
None so far.
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Stacking
Stacking Dist. DL6WU Formula (144.1 MHz)
E-plane 2.74 m or 9.0 ft
H-plane 2.34 m or 7.7 ft
Plot and data of 2 vertically stacked GTV 2-7w using DL6WU stacking distances
Antenna View & Elevation Pattern
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Plot and data of 3 vertically stacked GTV 2-7w using DL6WU stacking distances
Antenna View & Elevation Pattern
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Plot and data of 4 vertically stacked GTV 2-7w using DL6WU stacking distances
Antenna View & Elevation Pattern
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Plot and data of 4 in H-config stacked GTV 2-7w using DL6WU stacking distances
Elevation & Azimuth Pattern
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Excel version of AGTC_lite screenshot (Tsky = 290 K, Tearth = 5400 K)
Mind that this Yagi covers the whole 2 m band with a Return Loss better -35 dB or VSWR 1:03 in theory.
So the Antenna G/T will not be as low as you might be used to from comparaing a GTV Yagi to others in
the VE7BQH Antenna Tables.
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73, Hartmut, DG7YBN