Ladder Line The Almost-Utopian Feedline

If you’re just getting into ham radio or experimenting with antennas, you’ve probably heard of coax and maybe even window line. But then there’s something a bit more old-school and magical: ladder line.

What is Ladder Line?

Ladder line is a type of twin-lead feedline made up of two parallel wires held apart by insulating spacers—often plastic bars that look like the rungs of a ladder. Hence the name.

It might look simple, even outdated. But don’t be fooled. In many ways, it’s the most efficient way to get your signal from your radio to your antenna—especially when the antenna’s impedance isn’t a perfect match.

Why It’s Almost Lossless

Unlike coaxial cable, which can get quite lossy at high frequencies or under mismatch, ladder line has very low loss, even when the SWR is high. That means almost all your transmitter power makes it to the antenna—something coax simply can’t promise unless everything is perfectly matched.

The secret? Air. Ladder line is mostly air between the conductors, which has almost no loss. The plastic spacers barely interact with the RF signal. It’s like an RF highway with no speed bumps.

Where It Shines

Ladder line is perfect for:

  • Long wire antennas or doublets fed in the center
  • Multiband use with a tuner (especially one placed at the feedpoint)
  • Low-loss operation over long distances

It’s especially useful when you don’t know or care about the exact impedance of your antenna. While coax loses efficiency under mismatch, ladder line just keeps on going.

But It Has Quirks

It’s not all roses. Ladder line:

  • Can’t be run along metal gutters or stuck against a wall
  • Doesn’t like sharp bends or kinks
  • Needs a balanced tuner or a balun if you’re going back to coax

In short: it wants to float freely in the air, not be squished or grounded like coax.

Why Beginners Should Care

Because it’s forgiving.
You don’t have to design a perfectly resonant antenna. You don’t need precision-matched coax lengths. You can build a simple dipole, feed it with ladder line, and work multiple bands without rebuilding the whole thing.

And it’s cheap. A roll of ladder line costs less than premium coax and will outlast it in most cases.

Final Word

Ladder line isn’t just a throwback—it’s a smarter choice for many HF antennas. It’s simple, elegant, and almost lossless.

Once you understand its quirks, you’ll wonder why you didn’t use it from the start.

Don’t let the looks fool you—ladder line has outperformed coax for nearly 100 years.

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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 plat