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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.
antenna. Wire lengths for the 4:1 ratio in models 4932 and 4935. Usually any wire length that is non resonant on the band or bands desired will work with the 4:1 ratio. As an example, a 28-31 foot wire will typically allow 40 thru 10 meter coverage and a 43-50 foot wire will provide access to 80 thru 10 meters. Longer wire is always more
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.
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).
High Impedance UNUN for EHFW antenna The UNUN has a high impedance ratio (49:1 to 64:1) – not feasible to use transmission line transformers whose practical limit is about 16:1. It is a conventional transformer. Uses a ferrite toroidal core or cores (usually Type 43 or type 52 material). Most 1:4 and 1:9
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.
If the transformer is used with an external tuner in conjunction with a single wire antenna typically 130-135 feet in length, power should be reduced on those bands that show an SWR above 1.6 to 2:5 without the tuner.
