Stephan Schmid HB9EAJ has made available a PDF (in English) describing his portable 7-band End-Fed Half-Wave (EFHW) antenna
This document is about a multi-band shortwave (HF) amateur radio wire antenna that does not need an antenna tuner. The described antenna is based on the widely used end-fed half-wave (EFHW) dipole antenna design, improved for a bigger variety of bands, maximum efficiency and optimized for portable QRP communication.
The antenna system consist of a 20m-long radiator wire with one bypassable loading coil that in sum is resonant on the 60-, 40-, 30-, 20-, 17-, 15- and 10-meter bands, which I have never seen before. A small and efficient broadband transformer is used to match the impedance of this EFHW antenna to a 50Ω coaxial cable.
The document starts with the definition of the described EFHW antenna system, the author’s personal portable antenna requirements, the history of choosing and developing the described antenna system and then continues with antenna experiments and their conclusions.
Further, it gives some hints on how to build the proposed antenna system, as well as its compact backup antenna, and shows how to add additional bands to both of them.
Practical technical tips and references to other EFHW websites and documents complete the document.
Download PDF of A Portable 7-Band End-Fed Half-Wave (EFHW) Antenna
https://hb9sota.ch/wp-content/uploads/2021/08/Portable-7-Band-EFHW_HB9EAJ-V1.2.pdf
Read more – Southgate Amateur Radio News RSS Feed http://www.southgatearc.org/news/2022/july/portable-7-band-end-fed-half-wave-antenna.htm
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