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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.
Detailed Build Instructions for the 80-10 end-fed half-wave antenna with 49:1 unun: Noji-Article-80-10-EF-HW.pdf Source: https://noji.com/hamradio/pdf-ppt/noji/Noji-Article-80-10-EF-HW.pdf
An Easy Assembly Guide for a 49:1 EFHW (It doesn't even need to be this kit). The kit I use will get 4 bands (40,20,15.10) if wrapped this way. ...more. The video is geared towards you if you...
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).
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.
Attach a 2400 ohm resistor between the antenna wire and ground, and test using a SWR meter. SWR should be under 1.5:1. Alternatively, set up a half-wavelength wire outside and connect the matching unit with an antenna analyzer.
