Bart Your 80-meter dipole looks NVISish

Phil Anderson

Hi Bart,

I plugged in the numbers for your 80-meter dipole (using EZNEC)
for an apex at ~30 feet, freq of 3.550 and sloping legs of 63 feet
to 15 foot posts, an inverted V shape. Your (this) patttern
looks classic NVIS. VSWR was about 2.8 and the resistive
portion of the impedance was 23 ohms. I wouldn't change
a thing. Assume you use a match at your rig?

My 40-m NVIS dipole has the same classic NVIS azmuth pattern
but has 32 ohms resistance at the apex coaxial feed. Not much
difference, just a VSWR of about 1.9 to 2.1. I use the match inside
the FT450D to get the VSWR down to 1 to 1.

Unc Phil, W0XI

Phil Anderson


Oh forgot to mention, if you increased the height of your apex a few feet to roughly
0.66 of a quarter wavelength  the only thing that would change is a VSWR of 2.9 to 1.9.
Not worth climbing up for that. Contragulations.

Unc Phil


Wow!!! Phil thank you for doing that antenna calculation for me. That is very interesting and intriguing. I would never have thought that my dipole would be a true blue nvis.

We should be able to talk anytime regardless of condx!!

Thanks again es 72, Bart W0IIT
Pittsburg, KS