DG7YBN / 70 MHz / GTV 4m-10LT
  Last Update Aug. 08th 2014




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Performance Data and Geometry
Pattern and VSWR
Download as File


GTV 4m-10LT   with bent Driven Element



This Longyagi has a high F/B and altogether very little back lobe volume
The bent DE (K6STI style) transforms from low impedance to 50 ohms at feed point for direct feed.
The name "LT" reminds of the EF0210LT by YU7EF. This design here has slightly higher Antenna Temperature only
but more gain.




Performance Data

Gain vs. isotr. Rad.  14.5 dBi
Gain vs. Dipole       12.4 dBD
-3 dB H-plane         36.0 deg.
-3 dB E-plane         39.4 deg.
F/B                  -28.1 dB
F/R                  -26.0 dB
Impedance               50 ohms
Mechan. Length      10,402 mm
Electr. Length        2.43 λ

Geometry

Use EZNEC's Auto-Segmentation at 190 MHz.

The Drivers diameter is 16 mm


            Refl      DE      D1      D2      D3      D4      D5      D6      D7      D8
Pos.           0     585     863    1397    2406    3732    5362    7046    8769   10402     
Ele.        2110    2044    1978    1962    1914    1882    1844    1832    1794    1756
Diam.         12      16      12      12      12      12      12      12      12      12

Difference between simulation using high segmentation as given above and low segmentation per "Auto Segmentation" at 70.15 MHz
makes a delta of 0.15 MHz. With 12.5 mm per MHz on 70 MHz we need to add 1.8 mm to the ele. lenghts in this table to compensate the SBC.
Now we add the common BC on top of that and build a Yagi that is on correct frequency.








Pattern and VSWR Plots

Elevation and Azimuth plot at 70.15 MHz

 


RL and SWR plot - simulated










Downloads

EZNEC file of this Yagi (12 mm ele.)  









73, Hartmut, DG7YBN


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