From EME + SSB band to 145.5 MHz - Wideband Antenna Version (OWA-style)

This Yagi has an exceptionally low side- and back lobe volume for its length. It may serve as single antenna for Tropo, Meteor Scatter or even EME or make a very quiet contest antenna due to its high F/B and clean overall pattern. The bent DE (K6STI style) transforms from approx. 17 ohms to 50 ohms at feed point. The GTV 2-14 challenges the popular DK7ZB 12 ele. 28 ohms Yagi. Being just 0.15 λ or 312 mm longer it provides significantly better G/T at more bandwidth, s. data taken from VE7BQH G/T table (G/T is better the more positive the number is):

               Length.       Z         Gain      Gain of 4 Bay   Antenna Temp.   G/T of 4 Bay   VSWR Bandwidth
GTV 2-14w      8278 mm    50 ohms    14.1 dBD      20.0 dBD         218 K         -1.25 dB         1.07:1
DK7ZB 12 ele.  7960 mm    28 ohms    14.2 dBD      20.1 dBD         237 K         -1.49 dB         1.46:1          

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GTV 2-14w xpol built by Juan, EA4CYQ

Juan reports: "The antenna was as your design was made and the radiators got its resonance into your calculated length. That place was quiet and the antenna performed as expected, I will tell better than expected, the signal were amazing. At the end after 7 hours of activation I reached 42 QSOs, and the sensation is that the setup worked flawlessly." "The TX leg: a FT-857D with high stability accessory and a ITALAB amplifier running 700W. The RX leg: RFHAM LNA, FCDPP/FT-857D with splitter + LINRAD + MAP65 + WSJTX." This GTV 2-14w xpol is built on 25 x 25 mm and 30 x 30 mm, elements 8 mm. BC for the 30 x 30 mm stretch of boom is 10.2 mm plus SBC 1.7 mm = 11.90 mm. Offset between element planes is 520 mm. Boom end offset in any case is 40 mm. Insulators for 30 x 30 mm Boom are available at Spanish Co. Mastil https://mastil-boom.es/es/antena/452-aislador-boom.html Coax for the 1/4 wl stubs is 1/2 inch Cellflex.

Photos: above: "The 144MHz EME Newsletter, issues 2/2019 by DF2ZC, other: on courtesy of EA4CYQ

       

And a video showing details of the driver cell by Juan (tnx!!) It is .mov format.
I hope it plays well in your specific browser.

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GTV 2-14w built by Helmut, DK8SG
Boom is 25 x 25 mm, Elements 8 mm on 'insulators high on 25 x 25 mm' by 7arrays

6 x GTV 2-14w built by DR9A
Boom is 25 x 25 mm, Elements 8 mm on 'insulators high on 25 x 25 mm' by 7arrays
Click on image to enlarge:

Photo: DR9A Facebook ... first outing of new array in Marconi Memorial Contest 2018

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A GTV 2-14w X-pol shortened to 10 elements by Wolf, DF7KB

... and a 26 ele. DL6WU as "counterpoise". Note the Blade Dipole version for both planes made of thick stripes of aluminum. The GTV 2-14 minus 4 ele. keeps a relatively clean pattern, just loses a bit of band width and 1.7 dB of forward gain.

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2 x vertical stack of GTV 2-14w by DL2VL

These Yagis are built with Ø 8 mm ele. + standard insulators, DG7YBN on-boom-BC, mid boom section is 25 x 25 mm, front & rear section 20 x 20 mm.

And DL2VL/p in MMC 2016: Click the image to enlarge

This Yagi stack has been measured thoroughly, find real world Return Loss and pattern plots
that verify its simulated properties down the page

Marconi Memorial Contest, International Results 2017: DL2VL #13. QSO'S 319, points 114,252

ShowHide    < Official Results MMC 2015 for DL; DL2VL: "All in all I managed an All-Time-Location-Record."

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2016-04-12: GTV 2-14w on 25 x 25 mm Boom at Christian, DL8YE

A pretty antenna tree on top of his houses roof: 50 MHz: 6 ele. YU7EF, 2 m: 14 ele. DG7YBN, 70 cm: 23 ele. DK7ZB

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GTV 2-14w built by Radioclub Köszeg - HA1KYY
Good neighbourhood - DG7YBN 2 m GTV Long Yagi above a bay of DJ9BV 70 cm Long Yagis



ShowHide    Read Jozsef, HA1VQ's comments using the GTV 2-14w in contests

IARU Region 1 VHF Contest 2016

From their EDI Logfile: QSO's : 545, Points : 203474 km, QSOs > 800 km : 13, ODX: IT9IPQ JM78SG 1013 km. LY2WR 980 km, LZ9X 903 km, IS0/OE2UKL 892 km, 5P5T 890 km, LZ1KPW 865 km ... Station: Elecraft K3, TR144H+40, ZF Xtal Filter, 800 Watt Output, JN87FI, 741 m ASL & 1 x GTV 2-14w

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Jozsef's report from the IARU Region 1 VHF Contest 2015

"We worked without Preamplifier! With a TR144H+40, ZF Xtal Filter and K3 only, TX wise 800 Watt Output out of a GS31b. There was no particular Tropo acc. F5LEN and Hepbourn, but we could work into Sicily for the first time - IT9IPQ, JM78SG, 1013 km; further: IS0BSR, JN40PA, 998 km (Sardinia); LZ9X, KN22XS, 903 km and 4 QSOs > 800 km, 14 QSO > 700 km. For DX contacts we were even with stations using larger antenna array systems."

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Jozsef, HA1VQ on testing the new GTV 2-14 of HA1KYY in the 2014 IARU Region 1 VHF Contest

"Already after the first hours we could notice that the antenna has a quite orderly radiation characteristic, no audible side
lobes. HA1FV has a 6 m long F9FT at home, me a 6 m long DL6WU, we noticed a clearly better radiation characteristic on this
antenna. And now, after 24 hours (of contesting) I can say it works wonderful. Up to now we used the 6 m DL6WU and the difference
was tactual. Even though there was only a slightly bit of tropo the antenna delivers what we expected. We managed to complete
425 QSOs without LNA; despite a failure in our converter."

TX 800 W, 726 m ASL, JN87FI : Top QSOs: 7S7V 943 km; LZ9X 903 km; 5P5T 891 km; Z30A 825 km - avg. km/QSO 341 km

In the 2014 Marconi Memorial Contest HA1KYY did 356 QSO's and a valid score of
120248 points = 19th place in the IARU wide Multi-OP section with that single GTV 2-14w

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Note that HA1KYY works under difficult conditions - Jozsef: "HG1W is just 15 km from us, and running in excess of 3 kW Output and more than 20 dB antenna gain"

The Yagi is built on a 35 mm round boom, 8 mm elements + 13 mm clearence to boom with a BC of 8 mm incl. the SBC.

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Performance Data

ele. 1/4" ele. 8 mm Gain vs. isotr. Rad. 16.2 dBi 16.2 dBi Gain vs. Dipole 14.1 dBD 14.1 dBD -3 dB E-plane 29.8 deg. 29.8 deg. -3 dB H-plane 31.6 deg. 31.6 deg. F/B -33.0 dB -33.3 dB F/R -28.1 dB -28.3 dB Impedance 50 ohms = Mechan. Length 8278 mm = Electr. Length 3.98 λ Stacking Dist. h-pol. DL6WU top-to-bottom 3.82 m side-by-side 4.05 m Stacking Dist. h-pol. max. G/T top-to-bottom 4.00 m side-by-side 4.20 m

                                                          
        Pos.    Full Length    Full Length    Full Length      incl. BC    1/2 Length     Full Length      incl. BC
                 Free Space     Free Space     Free Space   on 25x25 Boom    in NEC        Free Space    on 25x25 Boom
                 incl. SBC     incl. SBC      incl. SBC
Refl.     0      1023.7         1023.3          1019.1        1026.7          508.5          1017.0         1026.3
DE(b)   232       983.7**        982.7          982.7           989.3       100-490.5        981.0          989.3
DE(a)   286       100.0          100.0          100.0           100.0         0-100           100.0          100.0
D1      421       972.2          971.3          967.2           974.3         479.5           959.0          968.3
D2      707       964.7          963.8          957.9           965.5         475.5´          951.0          960.3
D3     1246       943.1          942.0          936.1           943.7         463.75          927.5          936.8
D4     1886       928.0          926.8          919.5           927.1         455.5           911.0          920.3
D5     2628       916.3          915.0          907.9           915.5         449.2           898.4          907.7
D6     3419       905.1          903.8          895.3           902.9         443.0           886.0          895.3
D7     4239       893.7          892.2          884.1           891.7         437.0           874.0          883.3
D8     5086       885.1          883.8          875.3           882.9         432.5           865.0          874.3
D9     5939       879.3          877.8          869.5           877.1         429.5           859.0          868.3
D10    6771       878.9          877.3          868.5           876.1         429.0           858.0          867.3
D11    7580       871.9          870.3          862.3           869.9         425.5           851.0          860.3
D12    8278       859.9          858.4          850.1           857.7         419.0           838.0          847.3
                ele. 5 mm      ele. 1/4"       ele. 1/4"     ele. 8 mm*     ele. 8 mm*      ele. 8 mm*     ele. 8 mm*

• Insulated through Boom builds: => Use Full Length incl. SegmentationBC in Free Space Use DL6WU/G3SEK BC number for insulated through boom (add +3.4 mm to free length for 25x25 mm boom) or apply SM5BSZ's BC.exe (see my BC page ) for best fitting numbers for your boom and insulators.

• On Boom builds: => Use "incl BC on 25x25 mm boom" numbers and standard insulators plus M3 screw

SegmentationBC = +1.7 mm = (144.4 MHz - 144.1 MHz) * 5.85 mm/MHz
BaseBC (25x25) = +7.6 mm for semi-insulated on boom
Total          = +9.3 mm

(*) Note: element lengths for Ø 8 mm fit 5/16" too (**) Dipole diam. 0.375 in

The Drivers diameter is 10 mm for all examples. Use EZNEC's Auto-Segmentation at 350 MHz.

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This Yagi with 8 mm elements on a 25 x 25 mm boom with standard insulators

Ele. 8.0 mm DE 10 mm Boom 25 x 25 mm

"Ready to saw and drill" data for mounting elements on boom with BC according DG7YBN for standard insulators as sold by Konni, Nuxcom, WiMo, 7arrays:


Includes an SBC of 1.70 mm

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This Yagi with 8 mm elements on a 25 x 25 mm boom with high insulators by 7arrays.com

Ele. 8.0 mm DE 10 mm Boom 25 x 25 mm

"Ready to saw and drill" data for mounting elements on boom with BC according DG7YBN for type "insulator high 25 x 25 mm" by 7arrays:


Includes an SBC of 1.70 mm

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Sketch of Driver Cell



Note: DL2VL reports best match with the tips of the dipole bent backwards form the center line
by ~ 64 .. 69 mm = towards 217... 222 mm in the sketch above at a length of 979 mm*

*) with using carefully tuned 391 mm Ecoflex 10 + M3 soldering eyelets on as Quarterwave-to-gnd symmetrising line

Note: HA1VQ had to bring the ends of the bent Dipole quite a bit more straight again.
A good start would be to pick 255 mm as (b) for the tips instead of the 232 mm as per NEC geometry.

Sticking to the building scheme with semi-insulated on-boom elements and screw M3 and proposed BC + SBC
DL2VL reports a best RL at a distance of 69 mm from tips of DE to prolonged line of straight mid section.

  • Bent DE Online Calculator as web app

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Pattern and VSWR Plots

Elevation and Azimuth plot at 144.1 MHz

 

Real world azimuth plot of the 2 x vertical stack of GTV 2-14w
.. done by DL2VL with PolarPlot V3.2.7 Software. Tnx Jörg!
The PolarPlot V3.2.7 Software by Bob, G4HFQ is free for non commercial use. Link to G4HFQ's website


Mind that this is not a free space plot but a 2 x vertically stacked array at 18 m AGL.

Same conditions reconstructed in EZNEC V5+ (Perfect Ground)

Distance to TX ∼ 1000 m, avg. height 18 m AGL, pole diameters through Yagis 71 resp. 55 mm


Note:
(1) the slight unsymmetry in the pattern plot is to a certain extend due to reflections on the test range,
as other here plotted Yagis show same regular distortion.
(2) Nulls go no deaper than -40 dB because PolarPlot v3.2.7 is not able to record below -40 dB.

VSWR and Return Loss plots - simulated with 4nec2

and plotted real Yagi by Jörg, DL2VL with Rigol Analyser - On-Boom BC and QW-Line to gnd in place.
Note: due to the narrow band character of the Quarter Wave line made from H2010 trimmed to 144.2 MHz
(Q-factor) used for symmetrising, the Dip at 145 MHz is less intense then simulated.

Gain, F/B and F/R over Freq. - simulated with 4nec2

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X-pol Details

Table Set 1: On Boom 8 mm Elements

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There are two sets of tables provided:

(a) h- and v-plane for elements 8 mm on 25 x 25 mm boom
(b) h- and v-plane for elements 8 mm on 30 x 39 mm boom

Both use 520 mm or 1/ 4wl offset between h- and v-plane.
You may build with 25 mm throughout or any combination 25 and 30 mmm boom by picking the right corrected element length per plane and boom chosen.

This Yagi with 8 mm elements on a 25 x 25 mm boom with standard insulators

Ele. 8.0 mm DE 10 mm Boom 25 x 25 mm

"Ready to saw and drill" data for mounting elements on boom with BC according DG7YBN for standard insulators as sold by Konni, Nuxcom, WiMo, 7arrays:


Includes an SBC of 1.70 mm

This Yagi with 8 mm elements on a 30 x 30 mm boom with standard insulators

Ele. 8.0 mm DE 10 mm Boom 30 x 30 mm

"Ready to saw and drill" data for mounting elements on boom with BC according DG7YBN for standard insulators as sold by Konni, Nuxcom, WiMo, 7arrays:


Includes an SBC of 1.70 mm

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Downloads

EZNEC file of this Yagi with 3/16 inch elements  

EZNEC file of this Yagi with 5 mm elements  

EZNEC file of this Yagi with 8 mm elements  

EZNEC file of this Yagi as over stacked 4 bay (max. G/T)  

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Stacking

Stacking Dist. h-pol.    DL6WU     max. G/T
top-to-bottom           3.82 m      4.00 m
side-by-side            4.05 m      4.20 m