It is a resonant Half wave on 40m (7.1MHz) therefore also resonant on second, third and fourth harmonics etc. Due High Impedance feed point, the antenna is less height dependent. You can put it up at 10 or 50 feet in the air without much change in VSWR values.
Read great independent reviews at eHam website. This is perfect antenna for ALE HF-link stations, NVIS, MARS, ARES, EMCOMM etc. Various installations such as horizontal, vertical, as inverted V, as inverted L, zigzag etc. Measured VSWR in the gallery are taken with the antenna in an inverted V shape with the center of wire at 20 feet and ends a few feet above ground, your values could vary with way and height of installation.
(Grounding recommended for ESD protection). Resonant on 40/20/15/10m Works with a tuner on WARC bands 30/17 and 12M. Stealth #18 AWG tinned black wire.
No guarantee or liability is either expressed or implied pertaining to damages to persons, buildings, or equipment in the installation or use of our antennas. You must use extreme caution when working around power lines. If the antenna were to come into contact with a voltage carrying line it could be fatal. The item "HF End Fed Antenna EFHW-4010-1K / Installation-plate / LOW SWR/ 63 feet long" is in sale since Saturday, February 24, 2018.This item is in the category "Consumer Electronics\Radio Communication\Antennas\Ham, Amateur Radio Antennas". The seller is "myantennas" and is located in Tampa, Florida. This item can be shipped worldwide.