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This article will focus mainly on the antenna we built at Alan Parks, N7SHA, QTH. But the techniques used are applicable to any antenna installation. However we will focus on the specific of an end fed wire which apply to all end fed wires regardless of length.
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.
The impedance of a end fed wire can be anywhere from a few 10s of Ohms to a few thousand Ohms, depending on the frequency in use and the length of the wire. Other factors that can affect the impedance are bends in the wire, height above ground, proximity to buildings and wire diameter.
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.
Unlike the dipole antenna, which is comprised of two quarter-wavelength wires and fed at its center, the EFHW is a half-wavelength antenna with the coaxial cable for your transceiver attached at one end. It has become popular with portable operators because it’s very simple in its construction and deployment.
Attach Antenna wire to antenna frame winder (See Video for Sequence) **TUNE ANTENNA TO THE MIDDLE OF THE GENERAL PORTION OF 40M BAND 7.237. You should be good for 40, 20, 15 & 10 Meters. Enjoy your EFHW 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. (Adjustments to the length for your particular installation can move the resonance point to your preference).
