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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.
This project assembles a 49:1 ferrite-core (“FT”) type #43 transformer that matches 50 ohm input to 2500 ohm end fed antenna. It is optimized for 3.5/7/10/14 MHz but will work reasonably well on all amateur bands from 80 meters thru 10 meters with a 135 foot length of wire and a short connection to ground.
antenna is based on any number of parameters: specifically, the frequency or band of frequencies, location, directivity, and intended power range. This paper discusses some of the more important aspects of the End Fed Half Wave (EFHW) dipole antenna. The frequency band is HF (40 meters), and the intended power is 100 watts.
The counterpoise wire does not have to be similar in length to the main radiator and the antenna works best with counterpoise length of 0.05 λ on the lowest band the antenna wire is cut for. This calculates to ≈ 12.5 feet for an 80m end-fed.
4 sie 2020 · This is the page on the End-Fed Half-Wave antenna with a 49:1 transformer. This is a multiband antenna without the need for any tuner (which is the best type of antenna).
The end fed wire regardless of its length presents a high impedance to the feedline. If the intention is to build a ½ wave mono band antenna then it is necessary to attach a 48:1 unun at the feed point given the extremely high impedance. But if it’s a multi band antenna and is not ½ wavelength long on any of the intended bands then a 9:1 ...
5 cze 2021 · Here is a simple antenna calculator for two popular forms of ham radio HF wire antennas: the horizontal dipole and the inverted "V". (Updated June 5, 2021) The Antenna Calculator. for. Half-Wave Dipoles. Enter your desired frequency (MHz) of operation (i.e. 3.55).
