DG7YBN / 144 MHz / GTV 2-8n
  Last Update Apr. 28th 2013




.......



Performance Data and Geometry
Pattern and VSWR
Download as File
Stacking


GTV 2-8n Yagi   with bent Driven Element

EME + SSB narrow bandwidth version ... strictly G/T breeding

This medium length Yagi is gain oriented for maximum G/T at moderate T_ant for a Low Noise Yagi.
The bent DE (K6STI style) transforms from low impedance to 50 ohms at feed point for direct feed.





Performance Data

Gain vs. isotr. Rad.  13.6 dBi
Gain vs. Dipole       11.5 dBD
-3 dB H-plane         39.0 deg.
-3 dB E-plane         44.2 deg.
F/B                  -28.9 dB
F/R                  -25.1 dB
Impedance               50 ohms
VSWR Band Width     1.68:1 *
Mechan. Length        3820 mm
Electr. Length        1.84 λ

Stacking Dist. h-pol.
top-to-bottom         2.77 m
side-by-side          3.12 m

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



Geometry


                            
        Pos.    Full Length     incl. BC
                Free Space   on 20x20 Boom
				 
Refl.     0      1004.0         1010.2
DE(b)   194      100-471       100-474.1
DE(a)   275       0-100          0-100
D1      463       956.0          962.2
D2      867       938.0          944.2
D3     1510       914.0          920.2
D4     2302       894.0          900.2 
D5     3100       878.0          8842
D7     3820       850.0          856.2
 
                ele. 8 mm     ele. 8 mm
				
SegmentationBC = +2.3 mm = (144.6 MHz - 144.2 MHz) * 5.85 mm/MHz
BaseBC (20x20) = +3.9 mm for semi-insulated on boom
Total          = +6.2 mm				
Note: element lengths for Ø 8 mm fit 5/16" too

The Drivers diameter is 10 mm for all examples.
Use EZNEC's Auto-Segmentation at 380 MHz.


Sketch of Bent Dipole









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  









Stacking

 



Stacking Dist.    DL6WU Formula
H-plane               2.765 m
E-plane               3.116 m


Elevation and azimuth plot and data of 4 Yagi bay using DL6WU stacking distances

 

TANT screenshot


Gain vs. isotr. Rad.  19.5 dBi
Gain vs. Dipole       17.4 dBD
-3 dB H-plane         17.4 deg.
-3 dB E-plane         19.8 deg.
F/B                  -31.1 dB
F/R                  -26.5 dB
T_los                  5.0 K
T_ant                240.9 K*
G/T                  -4.29 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


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