Decided to change my plans for a trap dipole to a no-tune EFHW design since the trap dipole would have been just under 4 meters high and thus a cloudwarmer. However, if I mount an 80m inverted-L EFHW at the same height (so a mostly horizontal inverted-L), could I still get decent low-angle radiation at 40m and higher frequencies?
Also, does anyone know if a loading coil is used for 80m for the above antenna (so like 75 ft total), would it still radiate on the 80m harmonics?
If people are curious what resources I am using for design ideas, these are the main ones:
- Steve Nichols, G0KYA: http://infotechcomms.co.uk/downloads/Multi_band_EFHW.pdf
- Frank Dorenberg: https://nonstopsystems.com/radio/frank_radio_antenna_multiband_end-fed.htm
- Mike Mladejovsky, WA7ARK: http://hamfest.w7yrc.org/wp-content/uploads/2019/06/EFHWslides.pdf
- Steve Dick, K1RF: http://www.gnarc.org/wp-content/uploads/The-End-Fed-Half-Wave-Antenna.pdf
@KN4LIA if you haven't found this already, it might be helpful: http://hamfest.w7yrc.org/wp-content/uploads/2019/06/EFHWslides.pdf
i've been wondering much the same myself; going to rev up xnec2c soon and see if i can figure out how to get answers.
my hypothesis is that, being as they're both dipole-ish, you'll get about the same low-angle radiation pattern from either. of course, that pattern depends on the frequency, so hopefully both get better at higher frequencies? at first blush, i'd think the loading coil shouldn't change the harmonics much, but since the impedance of the coil varies by frequency, maybe it does!
@lm I finally got mmana-gal to work in wine on my linux system, so if I can successfully model the inverted L antenna I described, I will definitely share it with you here!
@lm This process has been complicated because 1) while I got mmana-gal to work on wine, it doesn't work perfectly, and 2) I don't know enough about the program to model a 1:64 impedance unun, so I have no idea what the SWR values would be with that added
What I need to do is actually get off my ass and read the Xnec2c manual and stop letting the black grid thing scare the shit outta me whenever the program loads
@KN4LIA you and me both!
there are a bunch of examples, including a 10-80m inverted L, to be had if you poke around /usr/share
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