Performance Data and Geometry
Pattern and VSWR
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GTV 2-9m Yagi with bent Driven Element
EME + SSB narrow bandwidth version ... strictly G/T breeding
This medium length Yagi is balanced between gain and Antenna Temperature. However providing a modest bandwidth compared to its sister design, the GTV 2-9n. In comparison to most of the entries with exceptional G/T around 2.15 wl in the 144 MHz VE7BQH G/T table its T_ant is approximately 5 ... 10 K lower. Thus it may be very useful in difficult RXing scenarios like contests or EME from within a city with a small size 4-Yagi-Bay only. The bent DE (K6STI style) transforms from low impedance to 50 ohms at feed point for direct feed.
Gain vs. isotr. Rad. 14.0 dBi Gain vs. Dipole 11.8 dBD -3 dB E-plane 38.4 deg. -3 dB H-plane 42.8 deg. F/B -27.3 dB F/R -26.7 dB Impedance 50 ohms VSWR Band Width 1.25:1 * Mechan. Length 4492 mm Electr. Length 2.15 λ Stacking Dist. h-pol. top-to-bottom 2.89 m side-by-side 3.21 m *) as in VE7BQH G/T table = at 145.00 MHz
Sketch of Bent Dipole
This design has been viewed how often after the first built has been published in Mar. 2018?
Pattern and VSWR Plots
Current distribution Elevation and Azimuth plot at 144.1 MHz
RL and SWR plot - simulated
EZNEC file of this Yagi with 8 mm elem.
• Plane Offset is 90 mm.
• Stacking Distance is 3.01 m as average of h-pol. and v-pol. distances acc. DL6WU
Stacking Dist. DL6WU Formula H-plane 2.851 m = 9.353 ft E-plane 3.163 m = 10.377 ft X-pol Stacking Dist. 3.01 m each plane
Elevation and azimuth plot and data of 4 Yagi bay using DL6WU stacking distances
Gain vs. isotr. Rad. 19.8 dBi Gain vs. Dipole 17.6 dBD -3 dB H-plane 17.2 deg. -3 dB E-plane 19.2 deg. F/B -30.6 dB F/R -28.8 dB T_los 4.3 K T_ant 228.5 K* G/T -3.81 dB*Theoretical numbers, no phasing line losses
nor imperfections caused by H-frame included
*) T_sky = 200 K, T_earth = 1000 K as in VE7BQH G/T table
73, Hartmut, DG7YBN