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An 80-10 end-fed half-wave antenna can be a very good performing part of an HF station. But its performance depends heavily on a well-designed and carefully constructed 49:1 unun, which matches the long wire impedance to within tuning range of operation. But the perfor-mance of an end-fed antenna is also very dependent on height above ground.
DIY. Worthwhile projects you can build on your own. 9:1 voltage unun. In a previous article, we discussed the end-fed antenna, and how it often exhibits a large im-pedance, anywhere from 1800 ohms to 5000 ohms. If your particular end-fed antenna exhibits. much lower impedance, like 450 ohms, or you’re attempting to match your 50-ohm coax to.
DIY. Worthwhile projects you can build on your own. The inverted-L Rybakov 806 antenna. The what? I’ve been looking for a good inverted-L antenna design that I could build, and hap-pened upon this version, which seems to have not only operator testimonials but technical data to support them.
A balun is to deal with differential vs single-ended, and a unun is a fixed transformer. The tuner is only needed if the antenna system isn't matched (usually 50 ohm), if the antenna gives the right impedance, your setup is already complete.
12 sie 2016 · A 9:1 unun is a transformer that reduces the impedance at the input by a factor of 9. So, if you connect a length of wire that presents an impedance of about 450 Ω to the input, you’ll get an impedance of about 50 Ω on the output. In fact, the 9:1 unun that I built is actually an autotransformer.
16 lip 2011 · Multiband antennas comprising a non-resonant length of wire that is fed via coax and an impedance transforming UnUn have become very popular of late - they are convenient and a low cost alternative to siting a remote tuner at the base of the vertical.
Utah Valley amateur Radio Club's Half Wave End Fed Antenna Detailed Build Instructions for the 80-10 end-fed half-wave antenna with 49:1 unun: Noji-Article-80-10-EF-HW.pdf
