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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.
Figure 2 shows the complete schematic view of a typical EFHW antenna system. Briefly, the 100pf/2kv cap across the primary of the impedance matching transformer is there to allow better tuning in the 10 meter band. The transformer is a step-up with an impedance ratio of 49:1, and wound on a type 43 toroid core.
• All antennas need to be as far as possible from ground, antennas, wires, homes and similar. • All antennas become more efficient when farther from ground or adjacent objects. • All antennas behave differently at different locations and in different configurations.
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).
Download The Mini 49:1 UNUN Instruction manual here. Antenna wire lenghts. The End Fed Half Wave antenna requires to cut one of halfwave lenghts.
With a 49:1 or 64:1 UNUN, no tuning is required and no antenna tuner is required (or perhaps a “touch up” tuner with up to 3:1 VSWR capability that many modern rigs have built-in.)
