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This EFHW antenna (patterned after one by Steve Ellington N4LQ, with notes by K1RF), if built carefully, will serve you for many years, and at up to 200 watts. The heart and engineering of its design is in its 49:1 impedance matching transformer, or unun (connects an unbalanced
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.
22 lut 2021 · The following is a list of materials required to make a 49:1 unun impedance transformer for an end-fed half wave antenna. You will also need a half-wavelength length of wire (14 or 12 gauge typically) in order to construct an antenna radiator for whichever ham band you choose.
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
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.
The 49:1 impedance transformer ( or 64:1 ) will help you bring down the high impedance of your resonant EFHW antenna to almost 50 Ohm. Let’s have a look at a few details on how to build a 49:1, or a 64:1 impedance transformer.
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).
