---
title: "Trace or U.FL jumper"
question: "When does a U.FL jumper beat a trace to the antenna?"
url: "https://nearfieldnotes.com/videos/ufl-jumper/"
site: "Near Field Notes"
video: "https://nearfieldnotes.com/media/ufl-jumper/full.mp4"
duration: "0:47"
date: "2026-11-08"
note: "https://nearfieldnotes.com/notes/ufl-jumper/"
---

# Trace or U.FL jumper (video)

When does a U.FL jumper beat a trace to the antenna?

0:47, with sound. [Read Note 25](https://nearfieldnotes.com/notes/ufl-jumper/) for the full answer, with figures, conditions and sources.

## Transcript

Trace or coax jumper?

Some boards send RF through a tiny coax cable instead of a trace.

Let's see when that pays off.

A trace loses a little every centimeter.

Most of it heats the FR-4 under it.

10 cm at 5.5 GHz: 39% gone.

The jumper pays a toll at its two connectors,

then the coax loses a fifth as much per cm.

So the lines cross.

Past 2 cm, the jumper wins.

At 2.4 GHz, past 3.

A thick 2-layer board gets a wide trace that loses less.

At 915 MHz, it wins up to 14 cm.

The coax is shielded too, so it can hop over noisy parts.

The catch: a hand-plugged cable, 30 mating cycles, and $1 or more in parts.

Short run or low band: trace. Long run at 5 GHz: jumper.

---

Source: https://nearfieldnotes.com/videos/ufl-jumper/