Build an Ultra-Portable End-Fed Antenna for QRP: Step-by-Step Guide

A ham radio operator running QRP field operations

Portable Ham Radio Antennas: The Best Lightweight End-Fed Build

Introduction

If you’re into QRP (low-power) radio operation, you’ll appreciate this ultra-portable end-fed antenna designed by David Del Torimo (DL1DN). It’s lightweight, efficient, and perfect for field use—ideal for operators who want to maximize performance with minimal gear.

Why does this matter? In QRP, every watt counts. A well-tuned end-fed antenna can mean the difference between a weak signal and a reliable connection, even at just 5 watts or less.

In this article, I’ll break down David’s build, go over the key components, and share a video at the end that dives deeper into optimizing your QRP setup.

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Creator Bio

David Del Torimo (DL1DN) is a passionate QRP operator and antenna experimenter. His QRP Lifestyle channel is packed with hands-on tips and DIY projects for ham radio enthusiasts, with a special focus on lightweight, efficient, and portable antenna setups.

🔗 Check out his channel for more QRP hacks: QRP Lifestyle on YouTube

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Key Takeaways And Notes

1. End-fed antennas are great for QRP. This build uses a 64:1 UNUN transformer for efficient impedance matching.
2. Portability matters. Weighing just 58 grams, this antenna is perfect for field ops and backpacking.
3. Tuning is everything. The right inductance and capacitance ensure your antenna works across multiple bands.

4. Some Notes About This Article

   1. 64:1 UNUN Transformer Misconception – The article states that the end-fed antenna uses a 64:1 UNUN, but this may not be suitable for all end-fed antenna configurations. A 49:1 UNUN is more commonly used for end-fed half-wave (EFHW) antennas, while a 64:1 is used for much higher impedance antennas (e.g., random wires requiring additional tuning).

   2. Toroid Core Selection – The FT50-43 toroid may not be ideal for a 64:1 transformer. This core is small and may not handle power efficiently. Larger cores like FT82-43 or FT140-43 are more commonly used in QRP applications.

   3. Inductor Value Issue – The article specifies a 34 µH inductor, but this value depends on the wire length and frequency range. If this is for a multi-band operation, the inductor value may need adjustment.

   4. Antenna Wire Length Inconsistency – The given lengths (0.95m + inductor + 2m) do not align with common resonant wire lengths for typical end-fed antennas. A traditional EFHW for 20m band should be around 10m (half-wave for 14 MHz) or a harmonic multiple.

   5. Capacitor Misplacement – A 100 pF, 1000V capacitor in the described position suggests it is being used for impedance matching, but EFHW antennas do not always require this. Typically, a capacitor (e.g., 150 pF - 220 pF) is placed across the transformer output to improve high-frequency performance.

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Materials You'll Need

Item	Purpose
SMA connector	Connects the antenna to your radio.
FT50-43 toroid	Acts as the core for the impedance transformer.
Insulated copper wire	0.25mm enamel wire recommended for winding.
Capacitor	100 pF, 1000V for circuit stabilization.
PVC pipe (28.5mm)	Used as a coil form for the inductor.
Glue or resin	Provides insulation and mechanical support.