DG7YBN / 144 MHz / GTV 2-11 LT
  Last Update July 28th, 2021


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Performance Data and Geometry
Pattern and VSWR
X-pol Details
Download as File
Stacking


GTV 2-11 LT  Yagi with bent Driven Element



This Yagi shows quite a low Antenna Temperature and a moderate gain for its length, which altogether is leading to a good G/T number. It may serve as a contest stack or medium size EME 4-Yagi-Bay, especially under tough RXing conditions.The bent DE (K6STI style) transforms to 50 ohms at feed point for direct feed.

This Yagi-Uda design makes maximum use of a 6.0 m off the shelf aluminium tube as boom without compromising on any design parameters to squeeze the electrical length into the given 6.0 m.


4 x GTV2-11LT xpol at OE3NFC

These Yagi sare built on 25 x 25 mm boom using 4 mm elements with SM5BSZ BC.exe Boom Correction,
held by 7arrays 4x6 mm insulators.     Click Images to enlarge

   

All four Photos on courtesy of Norbert, OE3NFC. Tnx!


2 x vertical GTV2-11LT above a GTV 70-25m, all built by Edy, YO2LSP

These 2 Yagis are built on boom 25 x 25 mm using 10 mm elements (click onto images to enlarge:





Edy, YO2LSP: "I finish and tested the new setup. It`s working great! New personal records for this location." ... tnx Edy!


2 x vertical GTV2-11LT built by YO2LSP, used in 2020 IARU ctest by YO5LD

Edy, YO2LSP: "I completed the construction of 2x11 elements and 4x5 and was used in the IARU contest by YO5LD
who succeeded an excellent results for the YO position. - 413 QSO`s , ODX - DA0FF @ 1028 km, Total: 192.955 points.
The antenna works fantastic, in special 2x11 element system. Thank you for your work." ... tnx Edy!


GTV2-11LT built by Sergey, R7MU










Performance Data

Specs: with 8 mm elements @ 144.1 MHz 

Gain vs. isotr. Rad.  15.1 dBi
Gain vs. Dipole       12.9 dBD
-3 dB E-plane         34.1 deg.
-3 dB H-plane         37.2 deg.
F/B                  -35.1 dB
F/R                  -29.7 dB
Impedance               50 ohms
VSWR Band Width     1.26:1 *
Mechan. Length        5920 mm
Electr. Length        2.85 λ

Stacking Dist. h-pol.
top-to-bottom         3.26 m
side-by-side          3.55 m

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


2x GTV2-11LT xpol at HB9W



GTV2-11LT and GTV70-25m built by PA2CV



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Geometry





Ø8 mm Elements - On Boom - Dimensions (BC acc. DG7YBN) 

		Refl	 DE(b)	 DE(a)	D1	D2	D3	D4	D5	D6	D7	D8	D9
Pos. 		0	 247	 285	420	680	1171	1817	2594	3434	4279	5130	5920
Boom 20x20 mm	1026.2	(992.2)	(100)	961.2	954.2	928.2	912.2	895.2	885.2	876.2	864.2	838.2
Boom 25x25 mm	1029.9	(995.9)	(100)	964.9	957.9	931.9	915.9	898.9	888.9	879.9	867.9	841.9


SegmentationBC = +2.3 mm = (144.7 MHz - 144.3 MHz) * 5.85 mm/MHz
BaseBC         = +3.9 mm for semi-insulated on boom (20 x 20 mm), 7.6 mm (25 x 25 mm)
Total          = +6.2 mm (20 x 20 mm), +9.9 mm (25 x 25 mm)				
Note: element lengths for Ø 8 mm fit 5/16" too

Ø10 mm Elements - On Boom - Dimensions (BC acc. DG7YBN) 

		Refl	 DE(b)	 DE(a)	D1	D2	D3	D4	D5	D6	D7	D8	D9
Pos. 		0	 247	 285	420	680	1171	1817	2594	3434	4279	5130	5920
Boom 20x20 mm	1020.2	(992.2)	(100)	956.2	948.2	920.2	904.2	886.2	876.2	866.2	855.2	828.2
Boom 25x25 mm	1023.9	(995.9)	(100)	959.9	951.9	923.9	907.9	889.9	879.9	869.9	858.9	831.9

Total-BC       = +6.2 mm (20 x 20 mm), +9.9 mm (25 x 25 mm)


For Elements 10 mm on a 25 x 25 mm boom

This table is only valid for:
Boom shape: square
Boom dim: 25 x 25 mm
Offset rear: 40 mm
Offset front: 40 mm

Note: This includes a "Segmentation Density Correction" (SBC) of 2.3 mm



The Drivers diameter is 10 mm for all examples.
The EZNEC model is done with Auto-Segmentation at 380 MHz




"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!

For Elements 3/16 inch through a 1 x 1 inch boom

This table is only valid for:
Boom shape: square
Boom dim: 1 x 1 in
Wall thickn.: 1/16 in
Holes in boom: 9.5 mm
Offset rear: 40 mm
Offset front: 40 mm

Note: This includes a "Segmentation Density Correction" (SBC) of 2.3 mm

Read abt. the SBC here .

Same conditions boom but for Elements 1/4 inch



For Elements 6.0 mm through a 25 x 25 mm boom

This table is only valid for:
Boom shape: square
Boom dim: 25 x 25 mm
Wall thickn.: 1.5 mmn
Holes in boom: 8.0 mm
Offset rear: 40 mm
Offset front: 40 mm

Note: This includes a "Segmentation Density Correction" (SBC) of 2.3 mm



For Elements 6.0 mm through a 1 x 1 inch boom

This table is only valid for:
Boom shape: square
Boom dim: 1 x 1 inch
Wall thickn.: 1/16 in = 1.6 mmn
Holes in boom: 8.0 mm
Offset rear: 40 mm
Offset front: 40 mm

Note: This includes a "Segmentation Density Correction" (SBC) of 2.3 mm



For Elements 6.0 mm through a TAPERED BOOM 20 x 20 mm > 25 x 25 mm > 20 x 20 mm boom

This table is only valid for:
Boom shape: square
Boom dim: 20 x 20 mm > 25 x 25 mm > 20 x 20 mm
Wall thickn.: 1.5 mmn
Holes in boom: 8.0 mm
Offset rear: 40 mm
Offset front: 40 mm

Note: This includes a "Segmentation Density Correction" (SBC) of 2.3 mm



Sketch of Bent Dipole








Pattern and VSWR Plots

Current distribution Elevation and Azimuth plot at 144.1 MHz

 


RL and SWR plot - simulated




GTV2-11LT Return Loss Plot by PA2CV

GTV2-11LT Return Loss Plot by OE3NFC









X-pol Details


xpol builders table 1: GTV 2-11LT, 4.0 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!

This table is only valid for:
Boom shape: square
Boom dim: 25 x 25 mm
Wall thickn.: 2.0 mm
Holes in boom: 6.0 mm
Offset rear: 500 mm resp. 570 mm
Offset front: 110 mm resp. 40 mm

Note: This includes a "Segmentation Density Correction" (SBC) of 2.3 mm

Read abt. the SBC here .

Elements in h-plane

Elements in v-plane





GTV 2-11 LT xpol with 3/16 inch elements

This table is only valid for:
Boom shape: square
Boom dim: 1-1/4 x 1-1/4 inch
Wall thickn.: 1.2 mm
Holes in boom: 9.5 mm
Offset rear: 500 mm resp. 570 mm
Offset front: 110 mm resp. 40 mm

Note: This includes a "Segmentation Density Correction" (SBC) of 2.3 mm

Read abt. the SBC here .

Elements in h-plane

Elements in v-plane


Same conditions boom but for Elements 1/4 inch

Elements in h-plane

Elements in v-plane




Downloads

EZNEC file of this Yagi with 8 mm elements  

EZNEC file of this Yagi with 4 mm elements  








Stacking 



Stacking Dist.    DL6WU Formula
E-plane               3.538 m
H-plane               3.261 m

Plot and data of 4 Yagi bay using DL6WU stacking distances

Elevation Pattern


TANT screenshot 


Gain vs. isotr. Rad.  21.0 dBi
Gain vs. Dipole       18.8 dBD
-3 dB H-plane         15.4 deg.
-3 dB E-plane         16.8 deg.
F/B                  -39.6 dB
F/R                  -32.8 dB
T_los                  4.5 K
T_ant                222.0 K*
G/T                  -2.51 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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