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Query: 2 elements yagi full siz
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A 40-meter reversible _Moxon rectangle_ antenna project details its construction and performance, featuring 51-foot long sides and 7.7-foot turned-in sections. The design incorporates a 16.5-foot boom, with elements spaced 1.1 feet apart, constructed from #14 covered wire. It utilizes two double-pole relays for switching between NE and SW directions, achieving F/B ratios up to 40 dB on CW and 30 dB on SSB, with distinct reflector stub settings for each mode. This antenna replaced a full-size 2-element Yagi, demonstrating comparable forward gain while offering superior F/B ratios and directional flexibility. _EZNEC_ modeling indicates only 0.2 dB less forward gain than the Yagi. The system uses no baluns, relying on half-wave feedlines and switched stubs for impedance matching. The antenna is tree-supported at 45 feet, with its effective radiation height modeled at 80 feet due to local terrain, enhancing its performance over a nearby lake.
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A great and efficient monoband VHF portable antenna. The article consist of two version of a 12.5 Ohm 3 elements yagi beam antenna plans for the two meter band, a full sized and a shortened version expecially designed for the SSB and CW on 144 MHz.
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A cost-effective alternative to the Optibeam OB10-3W, a high-performance but expensive tri-band Yagi antenna for the 20, 17, and 15-meter bands. The original Optibeam, featuring three full-size elements on each band, delivers strong forward gain and front-to-back ratio but comes with a high price tag. To address this, a custom design was developed, offering similar performance at a fraction of the cost. Using accessible materials and a simple 1:1 current balun, the homemade version proved highly effective, making it a practical solution.