DG7YBN / 144 MHz / YBN 2-9m
  Last Update Mar 3rd 2019


Performance Data and Geometry
Pattern and VSWR
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YBN 2-9m Yagi   with Straight Dipole

EME + SSB modest bandwidth version ... strictly G/T breeding with a straight dipole

This Yagi is a twin to the GTV 2-9m designed for those who yield to avoid producing and trimming a bent dipole. With rearranged driver cell this Yagi's performance is only a fraction away from the GTV version by means of losing just a marginal bit on the backlobes: F/B and F/R are down by approximately 1.5 dB compared to the GTV 2-9m.

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. Design date of issue: 2019.02.22

Current Profile

Performance Data

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                  -26.5 dB
F/R                  -24.5 dB
Impedance               50 ohms
VSWR Band Width     1.24:1 *
Mechan. Length        4492 mm
Electr. Length        2.15 λ

Stacking Dist. h-pol.
top-to-bottom         2.85 m
side-by-side          3.16 m

*) as in VE7BQH G/T table = at 145.00 MHz


This design has been viewed how often after the first built has been published in Mar. 2019?

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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.  


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


AGTC_anyGTa_2lite screenshot

Gain vs. isotr. Rad.  19.8 dBi
Gain vs. Dipole       17.7 dBD
-3 dB H-plane         17.2 deg.
-3 dB E-plane         19.4 deg.
F/B                  -29.3 dB
F/R                  -26.4 dB
T_los                  4.4 K
T_ant                470.5 K*
G/T                  -6.89 dB*
Theoretical numbers, no phasing line losses
nor imperfections caused by H-frame included
*) T_sky = 290 K, T_earth = 5100 K as in VE7BQH G/T table using ITU-R temps.

73, Hartmut, DG7YBN

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