Performance Data and Geometry
Pattern and VSWR
Download as File
GTV 2-14w Yagi with bent Driven Element
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
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.
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
that verify its simulated properties down the page
Marconi Memorial Contest, International Results 2017: DL2VL #13. QSO'S 319, points 114,252
< Official Results MMC 2015 for DL; DL2VL: "All in all I managed an All-Time-Location-Record."
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
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
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
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."
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
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.
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.
This Yagi with 8 mm Elements on 25 x 25 mm Boom, incl. DG7YBN BC and SBC = 1,7 mm
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
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
(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
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)
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
Elevation plot and data of 4 Yagi bay using DL6WU stacking distances
Gain vs. isotr. Rad. 22.15 dBi Gain vs. Dipole 20.00 dBD -3 dB H-plane 13.4 deg. -3 dB E-plane 14.4 deg. F/B -37.5 dB F/R -29.1 dB T_ant 218.8 K* G/T -1.25 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
Elevation and Azimuth plot and data of 4 Yagi bay using distances for max. G/T
Gain vs. isotr. Rad. 22.23 dBi Gain vs. Dipole 20.08 dBD -3 dB H-plane 13.0 deg. -3 dB E-plane 13.8 deg. F/B -36.1 dB F/R -28.3 dB T_ant 220.4 K* G/T -1.20 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