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![]() ![]() ![]() ![]() ![]() ![]() GTV 2-10 LT Yagi with bent Driven Element EME + SSB Low Temperature Version This Yagi has 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. Find details on this Yagi in • xpol configuration including SM5BSZ BC element cutting table • with bent folded dipole further down. A GTV 2-10LT built by F5UBZ Loic, F5UBZ reports "Hello, for info: I made gtv 2-10 LT antenna using your dimensions design (25 x 25 mm boom), first impression is very impressive. ... dipole box was made using a very nice box available at Conrad (Wiska COMBI 206)". A GTV 2-10LT built by I3QJZ A GTV 2-10LT built by DL2VL Chasing the famous and slightly longer EF0210LT by YU7EF .... . Using DL6WU formula derived stacking distances the GTV 2-10 produces just 2.9 K higher Antenna Temperature but better G/T and F/R. When "under stacked" at only 95 % of DL6WU distances it produces a lower T_ant and still better G/T, see table below: (Note: this is not the official VE7BQH G/T table; the GTV2-10 is not listed in there yet) Performance Data Elem. 4 mm Elem. 8 mm Gain vs. isotr. Rad. 14.4 dBi 14.5 dBi Gain vs. Dipole 12.3 dBD 12.3 dBD -3 dB E-plane 36.4 deg. 36.2 deg. -3 dB H-plane 40.0 deg. 40.0 deg. F/B -30.1 dB -30.1 dB F/R -26.3 dB -26.5 dB Impedance 50 ohms = Mechan. Length 5064 mm = Electr. Length 2.44 λ = Stacking Dist. h-pol. top-to-bottom 3.04 m side-by-side 3.35 m Geometry Metric Measures Versions for On-Boom-InsulatorsTable 1: This Yagi with 8 mm elements on a 20 x 20 mm boom with standard insulators
"Ready to saw and drill" data for mounting elements on boom with BC according DG7YBN for standard insulators as sold by HF Kits NL, WiMo, 7arrays: Includes an SBC of 2.3 mm Note: Element lengths for Ø 8 mm fit 5/16" too Table 2: This Yagi with 8 mm elements on a 25 x 25 mm boom with standard insulators
"Ready to saw and drill" data for mounting elements on boom with BC according DG7YBN for standard insulators as sold by HF Kits NL, WiMo, 7arrays: Includes an SBC of 2.3 mm Note: Element lengths for Ø 8 mm fit 5/16" too Imperial Measures Versions for mounting 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! Table 1: 4.76 mm = 3/16 inch El., Imperial Boom 1 x 1 x 1/16 inch and Metric 25 x 25 x 1.6 mm
This includes an SCB of 2.3 mm. Metric Measures Versions for mounting 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! Table 1: 4.00mm El., Metric Boom 25 x 25 x 2 mm
This includes an SCB of 2.3 mm. Bent DipoleThe Drivers diameter is 10 mm for all examples. Use EZNEC's Auto-Segmentation at 380 MHz. Sketch of Driver Cell ![]() • Bent DE Online Calculator web app ![]() ![]() Pattern and VSWR Plots Elevation and Azimuth plot at 144.1 MHz
RL and SWR plot - simulated Return Loss S11 (dB) simulated over a span of 120 - 160 MHz
and calibrated measurement lines, by ZS6JON Return Loss plot by DL2VL: Jörg reports best VSWR ie. Return Loss was more towards 144.2 before he shorted the Driven Element a little too far ![]() Downloads EZNEC file of this Yagi with 8 mm elem. ![]() ![]() EZNEC file of this Yagi with 4 mm elem. ![]() ![]() EZNEC file of this Yagi with 4 mm elem. and Folded Dipole ![]() ![]() ![]() 200 ohms version with Folded Dipole Right when I introduced the GT Yagi series I have shown that its possible to swap straight split dipoles with folded dipoles for any bent Driver Yagi (s. '144/432 MHz Long Yagis with a bent Driven Element' Dubus 1/2013 & Dubus Technik XII). The bent dipole delivers 50 ohms as straigth dipole and 200 ohms in its folded form; just as with any non-bent dipole. Use a λ/2 balun as with any other folded dipole, see here ![]() Here is the GTV 2-10LT using a Folded Dipole that is close to DJ9BV BVO 2 m Yagis Version: Outer straight Length = 990 mm, inner height = 50 mm, tubes Ø = 8 x 1 mm. Attention: Using a complete DJ9BV Folded Dipole with balun cut using v-factor only will not work out ending up at 144.3 MHz but around 143.9 MHz. At least the half wave balun must be measured & cut to act as a quarter wave stub while testing on half frequency of the foreseen i.e. 72.2 MHz for the 2 m band. Making it a build for the experienced maker that has a VNA. Bent tips rearbound by 30 mm, each a 100 mm from mid of boom on ... and insert. ![]() Cross Yagi / X-Pol on boom 25 x 25 mm with elements through boom Simulated DE offset of 16 mm for mounting a straight split DE below or on top of the 25 mm boom in a narrow plastic case Elements are of diameter 4 mm, so the DJ9BV nylon rivet methode can be uses to mount elements insulated through boom. on boom offset: second (vertical plane) = 550 mm Element table for building with the advanced SM5BSZ BC applied on 25 x 25 x 2.5 mm boom, 6 mm holes in boom for nylon rivets. Offset on both ends is 30 mm Element table for building with the advanced SM5BSZ BC applied on 20 x 20 x 2.0 mm boom, 6 mm holes in boom for nylon rivets. Offset on both ends is 30 mm Mounting elements with funiture hole plugs from the Do-It-Yourself market (LDPE). Drill holes of 3.9 mm for 4 mm elements. This will also work with thicker diameters as 5, 6 or 8 mm. But BC and element lengths needs to be adapted via my MS Excel Yagi Element Configuration Tool, see here
Performance Data, single (horiz.) polarisation) Gain vs. isotr. Rad. 14.42 dBi Gain vs. Dipole 12.3 dBD -3 dB H-plane 40.0 deg. -3 dB E-plane 36.2 deg. F/B -30.0 dB F/R -25.3 dB Impedance 50 ohms VSWR Band Width 1.34:1 * Mechan. Length 5614 mm Stacking Dist. top-to-bottom 3.19 m side-by-side 3.19 m *) as in VE7BQH G/T table = at 145.00 MHz
![]() Stacking Stacking Dist. DL6WU Formula H-plane 3.35 m E-plane 3.04 m Data of 2 Yagi stack using DL6WU stacking distances an "urban" low noise solution: two times GTV2-10LT vertically polarised; just a 3 m aluminum rod and a Yaesu G5500 azim./elev.-rotor combination or similar will do for digital EME Gain vs. isotr. Rad. 17.4 dBi Gain vs. Dipole 15.3 dBD F/B -31.3 dB F/R -28.5 dB T_ant 219.5 K* G/T -6.02 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 Elevation and azimuth plot and data of 4 Yagi bay using DL6WU stacking distances
Gain vs. isotr. Rad. 20.4 dBi Gain vs. Dipole 18.2 dBD -3 dB H-plane 16.2 deg. -3 dB E-plane, 18.0 deg. F/B -32.6 dB F/R -29.7 dB T_ant 227.7 K* G/T -3.18 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 |