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half-wave antennas. An end-fed half-wave (“EFHW”) antenna has a very high feedpoint impedance, often 1000 to 5000 ohms (depending on the diameter). The radiation pattern on the fundamental frequency (where the antenna is 1/2 wavelength) will be similar to the same wire fed in the center as a dipole (but this is not the case on harmonics).
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).
Antenna radiation pattern depending on length and height. In the images below, I hope to clarify how length and antenna height affect the antenna radiation pattern. In many cases, the available space around the house determines the size and height of the antenna.
19 sty 2017 · I want to use an end-fed wire antenna, but what would be the best length of wire for the 20m and 40m bands? Is there a way to work this out? This is assuming a tuner will be used.
14 sie 2024 · An EFHW (End-Fed Half-Wave) Antenna is a type of radio antenna commonly used in amateur radio. It is designed to be fed at one end, hence the name, and is typically half the length of the radio wave it is intended to transmit or receive.
The random wire antenna is probably one of the least expensive, easiest and cheapest HF antennas to use if you have a tuner and you want to get the "most" out of a length of "random" wire without having to pull out that calculator, doing the math, getting the center insulator built or bought, running the feedline, and all the rest that goes ...
This makes the end-fed antenna perfect as a multi-band antenna. Just look at the following example: 20 meter wire is a half wavelength for the 40 meter band, two half wavelengths for the 20 meter band, four half wavelengths for the 10 meter band and 3 half wavelengths for the 15 meter band.
