Performance Data and Geometry
Pattern and VSWR
Download as File
GTV 2-12m Yagi with bent Driven Element - Mark 2 design
Link to the mk1 design website
EME + SSB band version
The redesigned Yagi shows even lower back lobes and T_ant then the initial design. Gain dropped by 0.07 dB but G/T increased by 0.02 dB due
to much lower Antenna Temperature whilst yielding more bandwidth. It may serve as single antenna for Tropo, MS or even EME or make a quiet
contest antenna due to its high F/B. The bent DE (K6STI style) transforms from approx. 17 ohms to 50 ohms at feed point.
GTV 2-12m mk2 by IK2FIV
The Yagi is built on 25 x 25 mm boom, 8 mm el. on standard holders by 7arrays.
With "second operator" for backup.
Photo credit & Return Loss plot: IK2FIV. Thank you Marco!
Marco trimmed it to the start of band for EME purpose.
GTV 2-12m mk2 by YO2LSP
Edy, YO2LSP reports:
"I have built for me - 144 MHz / GTV 2-12m mk2. Is in use for more than 6 month and is working very well."
Photo credit: YO2LSP. Thank you Edy!
GTV 2-12m mk2 by G1YFG
Robin, G1YFG built the dipole fastening plate from 10 mm Polycarbonate (lexan/makrolon) cut his CNC machine.
"It has a 3 mm deep by 20 mm wide slot to align it on the boom, it has 6 mm x 3 mm slots with 2 x bolts for the elements."
Photo credit: G1YFG. Thanks Robin!
A slightly modified GTV 2-12m mk2 built by Hans-Jörg Dierking, DJ6CA. Link to his website with building hints
Jörg used a 20x20 mm boom, 8 mm elements, standard on boom insulators by Konni-Antennen and 6.3 mm of BC
The 6.3 mm hold the 2.0 mm of SBC + 3.9 mm YBN On-Boom-BC with standard insulators + 0.4 mm for including the top pieces
that Konni-Antennen offers additionally to the base insulator. Well done!
GTV 2-12 mk1 built by DG7YBN on 20x20x1 mm boom, ele. 8 mm, lightweight /P version used in Contest at DL0IA/p
GTV 2-12m mk2 built by DK5EW
Comparism of mk1 and mk2 design in G/T table format
Note that this is not a clipping of the official 144 MHz G/T Table but my own compilation.
Link to the official 144 MHz G/T table by VE7BQH with this Yagi named 'DG7YBN 12 Ver2'
Gain vs. isotr. Rad. 15.5 dBi Gain vs. Dipole 13.4 dBD -3 dB E-plane 32.0 deg. -3 dB H-plane 34.2 deg. F/B -31.2 dB F/R -28.0 dB Impedance 50 ohms Mechan. Length 6781 mm Electr. Length 3.26 λ Stacking Dist. h-pol. DL6WU max. G/T top-to-bottom 3.54 m 3.82 m side-by-side 3.77 m 3.99 mGeometry
Pos. Full Length Free Space incl. BC incl. BC Free Space incl. SBC on 20x20 Boom on 25x25 Boom Refl. 0 1008.0 1010.0 1013.9 1017.6 DE(b) 238 100-(968) 100-(970.0) 100-(973.9) 100-(977.6) DE(a) 296 0-100 0-100 0-100 0-100 D1 431 959.0 961.0 964.9 968.6 D2 715 951.0 953.0 956.9 960.6 D3 1256 927.5 929.5 933.4 937.1 D4 1896 911.0 913.0 916.9 920.6 D5 2638 898.4 900.4 904.3 908.0 D6 3424 886.0 888.0 891.9 895.6 D7 4286 874.0 876.0 879.9 883.6 D8 5150 866.0 868.0 871.9 875.6 D9 6007 856.0 858.0 861.9 865.6 D10 6781 842.0 844.0 847.9 851.6 ele. 8 mm ele. 8 mm ele. 8 mm ele. 8 mm • Insulated through Boom builds: => Use column "Free Space incl. SBC" and add thru Boom BC. Use DL6WU/G3SEK BC number for insulated through round boom (add +3.4 mm 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 column "incl. BC on 25x25 mm boom" for standard insulators plus M3 screw SegmentationBC = +2.0 mm = (144.65 MHz - 144.30 MHz) * 5.85 mm/MHz BaseBC (25x25) = +7.6 mm for semi-insulated on boom // exchange with +3.9 mm for 20 x 20 mm boom Total = +9.6 mm to be added to "Full Length Free Space (ex. SBC)"
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 350 MHz.
To add a BC on the DE is a strictly individual measure due to the actual height above the boom.
For same heigth as elements use full "On Boom BC"; for double that or more use added SBC only.
• For details on the On-Boom BC see here
• For details on DE and BC on it see here
• Bent DE Online Calculator as web app
How many OMs have been looking up this design? (since Nov. 2015)
Pattern and VSWR Plots
Elevation and Azimuth plot at 144.1 MHz
SWR and Return Loss plots - simulated with 4nec2
EZNEC file of this Yagi
Elevation plot and data of 4 Yagi bay using DL6WU stacking distances
Gain vs. isotr. Rad. 21.46 dBi Gain vs. Dipole 19.31 dBD -3 dB H-plane, 14.4 deg. -3 dB E-plane, 15.4 deg. F/B -34.0 dB F/R -32.2 dB T_ant 222.9 K* G/T -2.02 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
Data of 4 Yagi bay using distances for max. G/T
73, Hartmut, DG7YBN