End Fed Long Wire Antenna



From the point of view of efficiency, tuning an antenna to resonance at the fre-quency of transmission makes sense in that it ensures maximum transfer of power, which is all well and good until we QSY to another frequency, forcing a need to re-tune or acceptance of the impedance mismatch and reflected power in the feed-line.

An End-Fed Half-Wave (EFHW) is an antenna that is a half-wavelength at the lowest frequency of operation, making the odd and even harmonics of the fundamental frequency available across the bands for which it is designed to work; even so, an antenna tuner is worth having to ensure a 50 Ω load to the transmitter, though not strictly necessary.

Having tried resonant antennas and a sloping EFHW, I thought to make things eas-ier by using an End-Fed Long-Wire (EFLW) which is non-resonant on any operating frequency, in conjunction with a 9:1 UnUn, a choke, and automatic antenna tuner; the antenna itself configured either as a sloper or an inverted-V, the idea being to let the antenna tuner take care of business, leaving me to get on with making QSOs.

PDF with Pictures

Posted in Ham Projects.

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