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9 lip 2020 · Isolation balun transformers are RF transformers with the unbalanced side tied to ground and the balanced side connected to the load. Similarly to standard RF transformers, the ratio of windings can also be used to create an impedance transformation.
24 sty 2024 · An Unun, short for Unbalanced to Unbalanced, is a type of transformer used in RF antenna systems to match impedance between an unbalanced antenna and an unbalanced transmission line. It is designed to convert the impedance of the antenna to a value that is better suited for the transmission lines.
22 lut 2021 · The following is a list of materials required to make a 49:1 unun impedance transformer for an end-fed half wave antenna. You will also need a half-wavelength length of wire (14 or 12 gauge typically) in order to construct an antenna radiator for whichever ham band you choose.
29 mar 2023 · What is an impedance transformer? The impedance transformer is often confused with the balun and unun, while the impedance transformer does only one thing. Transforming the impedance of the antenna to that of the feed line and thus the receiver and transmitter.
11 lut 2015 · A current balun can present a high impedance to common-mode signals, which will help reject noise. Common mode signals are the same on both conductors, so are not "balanced" or differential. An unun is an impedance transformer, usually 4:1 or 9:1, which matches an unbalanced antenna to a feedline.
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.
These are sometimes known as a Magnetic Longwire Balun. Its really an impedance transformer (9:1) to feed a high impedance, end fed (unbalanced) random wire which is likely to be a few hundred ohms, and transform it into something closer to a 50Ω (unbalanced) coaxial input, hence UnUn.
