DG7YBN / 144 MHz / YBN 2-9m
  Last Update Mar 30th 2020


.......




Performance Data and Geometry
Pattern and VSWR
Download as File
Stacking


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


Geometry



        

Table 1: YBN 2-9m, 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

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
  



Note: with through Boom BC it is important to stick to the boom end offsets given below!

Note: This includes a "Segmentation Density Correction" (SBC) of 1.75 mm





        

Table 2: YBN 2-9m, 8 mm elements on a 20 x 20 mm boom:


"Ready to saw and drill" data for mounting elements on boom with standard insulators. BC according DG7YBN:


Boom shape: square
Boom dim: 20 x 20 mm
  


Note: This includes a "Segmentation Density Correction" (SBC) of 1.75 mm




Table 3: YBN 2-9m, 8 mm elements on a 25 x 25 mm boom:


"Ready to saw and drill" data for mounting elements on boom with standard insulators. BC according DG7YBN:


Boom shape: square
Boom dim: 25 x 25 mm
  


Note: This includes a "Segmentation Density Correction" (SBC) of 1.75 mm




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

Flag Counter






Pattern and VSWR Plots

Current distribution Elevation and Azimuth plot at 144.1 MHz

 


RL and SWR plot - simulated








Downloads

EZNEC file of this Yagi with 8 mm elem.  








Stacking 



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



Flag Counter