ATU-100 Auto Antenna Tuner 100W – N7DDC DIY Radio Tuner

ATU-100 Automatic Antenna Tuner 100W by N7DDC

Take your amateur radio setup to the next level with the ATU-100 Automatic Antenna Tuner, a high-performance DIY tuner based on the renowned N7DDC design. Whether you're a seasoned ham radio operator or an enthusiastic builder, this 100W auto tuner delivers precise impedance matching across a wide range of frequencies — helping you get the most out of every transmission.

Built to handle up to 100W of working power and capable of measuring up to 150W, the ATU-100 features intelligent automatic tuning that kicks in with as little as 5W of input power. Its broad inductance and capacitance range ensures compatibility with a wide variety of antenna types, making it an incredibly versatile addition to your shack. Made in Mainland China.

Key Features

• Automatic Tuning: Starts tuning automatically with just 5W of input power
• 100W Working Power: Handles up to 100W continuously, with up to 150W peak measurement capability
• Wide Supply Voltage: Operates on 10–15VDC for flexible power options
• High-Resolution Power Measurement: 0.1W resolution below 10W, 1W resolution above — with ±10% accuracy
• Broad Inductance Range: Up to 8.53µH maximum installed inductance, with a 0.05µH minimum step
• Wide Capacitance Range: Up to 1,869 pF maximum installed capacitance, 10 pF minimum step
• Low Power Consumption: Typical draw of only 100–200 mA (max 400 mA)
• N7DDC Design: Based on the trusted, community-proven N7DDC open-source schematic
• DIY-Friendly: Perfect for builders and hobbyists looking to customize their radio setup

Technical Specifications

What's in the Box

• 1 × ATU-100 Radio Antenna Tuner (plug not included)

Note: This product is regularly upgraded. Appearance and color may vary from images shown. Please consider this before placing your order if specific color or appearance is required.

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Frequently Asked Questions

Q: What is the minimum power needed to activate the ATU-100 automatic antenna tuner?

A: The ATU-100 automatic antenna tuner requires a minimum of 5W of input power to initiate the automatic tuning sequence. This makes it compatible with a wide range of transceivers, including low-power QRP rigs running at 5W or more.

Q: Is the ATU-100 antenna tuner compatible with all antenna types?

A: The ATU-100 is designed to match a broad variety of antenna configurations thanks to its wide inductance range (up to 8.53 µH) and capacitance range (up to 1,869 pF). It works well with wire antennas, verticals, and other common amateur radio antenna types, provided the impedance mismatch falls within its tuning range.

Q: Does the ATU-100 come fully assembled or as a kit?

A: The ATU-100 is supplied as a single assembled unit (1 piece). It is based on the popular N7DDC open-source design and is popular among DIY ham radio enthusiasts. Please note that a power plug is not included in the package.

Q: What voltage does the ATU-100 antenna tuner require?

A: The ATU-100 operates on a DC supply voltage in the range of 10–15 VDC, with a maximum current draw of 400 mA. Typical operation draws only 100–200 mA, making it energy-efficient for continuous use in your radio shack.

Production & Packaging Notice

To maintain high stock availability and fast shipping times, our items are sourced from multiple verified manufacturing facilities. While the core quality, materials, and product specifications remain identical, you may notice slight variations in the packaging design, manufacturing origin, or the wording of the printed instructions.