NECtasy and the Myth of the Perfect Polar Plot

Ah, NEC. The Numerical Electromagnetics Code. The sacred crystal ball of the modern ham. From EZNEC to 4NEC2 to MMANA-GAL, thousands of operators across the globe load up their favorite simulator, click a few wires into place, hit 'Run', and bask in the glow of the polar plot.

Behold! 7.1 dBi at 18 degrees elevation. Forward gain! Nulls! Lobes! A miracle in ASCII.

But there's a problem.

Welcome to the Ideal World (Population: 0)

NEC doesn’t live in your backyard. It lives in an imaginary paradise where:

  • Ground is perfectly homogeneous, flat, and lossless — or whatever lossy value you feed it in a single number.
  • The weather is static. There is no wind, no heat, no snow, and no "I forgot to guy my mast" scenario.
  • Coax doesn’t have loss. Ferrite doesn’t saturate. The cat doesn’t chew through your radial.
  • All conductors are perfect, with no corrosion, no oxidation, and no splices made in the dark.

I2R Loss? Never Heard of Her

NEC also doesn’t care about the most painful issue for EFHW fans: transformer losses. That hot, sweating, overworked ferrite core dissipating 60 watts of heat at the third harmonic? NEC just shrugs. "That’s not my department."

Try modeling an EFHW with a 49:1 transformer outside its resonant band. The polar plot says 2.7 dBi at 35 degrees. Your shack says 0.0 dB and a suspicious burning smell.

Elevation? Ground? Did Someone Say Variable Soil?

Your real backyard consists of patches of clay, gravel, that one cursed tree, and your neighbor's buried electric dog fence. NEC assumes you're operating on a vast prairie of uniform dielectric.

And then there's elevation: you live on a slope. NEC lives in Kansas.

NEC Is Not a Weather App

Cold winter day? That vertical now radiates differently.

Hot summer afternoon? Your PVC insulators are sagging, and resonance has drifted.

Windstorm? One radial is now flapping in the breeze like a tuning fork. Good luck seeing that in 4NEC2.

Simple Antennas? Use a Brain, Not a Solver

Dipoles, verticals, end-feds... all can be understood by:

  • Following the current distribution.
  • Comparing physical length to wavelength.
  • Checking for balance or asymmetry.

You don’t need 3D mesh grids and 10,000 segments to understand that a quarter-wave with one radial points in that radial's direction. It's not quantum mechanics.

Where NEC Shines

NEC is a useful tool — for complex systems:

  • Multiband Yagis
  • Phased Transmit arrays
  • Bobtail curtains
  • Half-square setups
  • Antennas with parasitic elements and reflectors

Here, it helps visualize interactions that are hard to see otherwise.

But for Simple Antennas...

Using NEC for a vertical is like using a particle accelerator to open a peanut.

If your antenna has two wires and fits in your car, maybe all you need is:

  • A tape measure
  • A current meter
  • A cup of coffee

Skip the simulation. Understand the system. You'll probably reach the same conclusion — without needing to Google "how to set ground type in MMANA-GAL" at 3 a.m.

Final Thought

NEC won’t save your signal. Physics will.

The views expressed in this article are occasionally a bit exaggerated ;), frequently sarcastic ;), and always written with a spark of humor ;). While the technical points are grounded in real-world experience, the tone is intentionally playful to challenge assumptions, provoke thought, and perhaps make the reader laugh a little.

If you recognize your setup in here — don’t worry. We’ve all been there. The goal isn’t to mock, but to move the hobby forward with a bit more clarity, a bit less noise, and a healthy dose of fun.

Serious about performance. Not always about tone.

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Written by Joeri Van Dooren, ON6URE – RF, electronics and software engineer, complex platform and antenna designer. Founder of RF.Guru. An expert in active and passive antennas, high-power RF transformers, and custom RF solutions, he has also engineered telecom and broadcast hardware, including set-top boxes, transcoders, and E1/T1 switchboards. His expertise spans high-power RF, embedded systems, digital signal processing, and complex software platforms, driving innovation in both amateur and professional communications industries.