KL503 12V HF Linear Amplifier – 25–30 MHz | Up to 300W Output Power

Boost Your Signal – Dominate the Airwaves

The KL503 is a high-performance HF linear amplifier designed for amateur radio operators who demand more power, greater range, and rock-solid reliability. Whether you're reaching out across town or across continents, the KL503 ensures your signal gets there strong and clear.

🔧 Key Features:

• Wide Frequency Coverage: Operates from 25 MHz to 30 MHz – ideal for 10-meter amateur band radios.
• High Output Power: Up to 300W PEP output power, depending on input drive.
• Input Power Flexibility: Accepts input from 1-5W in both AM and SSB. Suitable for QRP radios. If your radio transmits higher, for example 12W in SSB, you MUST lower the power of the radio to avoid unrepairable damage to the amplifier.
• 6 High-Power Transistors: Delivers consistent performance under demanding conditions.
• Built-in Protection: Includes protection for polarity inversion and a temperature-activated cooling fan to keep performance stable.
• Compact & Durable: Rugged aluminum heat sink case, with a low-profile footprint that fits seamlessly in your mobile or base setup.

⚙️ Technical Specifications:

• Power Supply: 12–14V DC
• Input Power:
  • AM/FM: 1-5W
  • SSB: 1–5W
• Output Power:
  • AM/FM: Up to 180W
  • SSB: Up to 300W
• Current Drain: 14–28A (typical)
• Cooling: Internal temperature-controlled fan
• Dimensions: 170 x 295 x 62 mm
• Weight: Approx. 1.4 kg

✅ Applications:

Perfect for amateur radio operators, DX hunters, and radio enthusiasts looking to enhance transmission range and clarity with a reliable and compact amplifier.

Note: This amplifier is intended for licensed amateur radio use. Always ensure compliance with your local regulations regarding power output and frequency use.

🇨🇦 Looking to Buy in Canada?

This product is available through Fleetwood Digital, a trusted Canadian source for amateur radio and CB equipment. Shop with confidence — no cross-border delays, no duties, and expert local support.

Please note, linear amplifiers require appropriate licensing to install and operate. These units are not designed for a 100% duty cycle. All units are fully tested and inspected before shipping; however there are no returns and a limited (Manufacturers) warranty applies. Setup and testing should only be performed by qualified individuals.