After optimizing Folded Dipole Element separation, SWR was further reduced to under 1.4 with up to 0.25 dB more gain on Ch13 than K6STI's Yagi RevA, with small increase in F/R and F/B (except Ch12-13 decreased some). I also investigated a Folded Dipole variant which has a Characteristic Impedance of 300 ohms (vice 75-ohm for above). Note that 4nec2 calculated SWR is slightly higher than K6STI's. This is different than the worst side-lobe level calculated by K6STI. And F/B is ratio of gain exactly towards the front to gain towards the rear with an included angle of (my choice) +/- 45-deg. In 4nec2 analyzes, F/R is the ratio of gain towards the front (azimuth = 90-deg) to gain towards the rear (azimuth = 180-deg). On 19Jun he replaced Original with slightly revised RevA, which has improved SWR and Gain: K6STI's Optimized Yagi design is only 31.4-inches long and 32.4-inches wide, but provides good coverage across all Hi-VHF channels (Ch7-13) with excellent Front-to-Rear (F/R) and Front-to-Back (F/B) Ratios and moderate (7.4-9.3 dBi) Net Gain.Īlthough slightly longer, performance differences between versions are very small, mostly reflecting fine tuning. The initial input is a really trivial 2 elmenent yagi.īrian Beezley, K6STI, used his AO 8.06 Antenna Optimizer to find a configuration that minimized response to the rear. This java applet/application implements a simple yagi modeling code.
Yagi Calculator is a Windows program that also runs well on Linux, Ubuntu 8. 4nec2 files can also be imported into EZNEC and other antenna simulation programs. Save as *.txt format then rename as *.nec. 4nec2 files are included in *.doc format, providing all dimensions. Hi-VHF 5-El Yagi Optimized by K6STI holl_ands >Hi-VHF 5-El Yagi Optimized by K6STI K6STI's Hi-VHF 5-Element Yagi with Rearward Swept Driver Element analyzed using 4nec2.
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