Item Description

The LDG AT-100 ProII Automatic Antenna Tuner is a high-performance HF antenna matching unit designed for reliable operation across 1.8–54 MHz, suitable for both base station and semi-professional amateur radio installations.

Built for flexibility and ease of use, the AT-100 ProII features dual antenna switching, allowing instant selection between two antenna systems with independent memory storage for each output.

With LDG’s advanced memory tuning system, the unit stores over 4,200 frequency memories, enabling near-instant recall of previously tuned settings for faster band changes and improved operating efficiency.

Manufactured by LDG Electronics, this tuner is widely respected for its reliability, fast tuning performance, and intelligent automatic operation.

Key Features

• Automatic HF antenna tuner (1.8–54 MHz coverage)
• Handles up to 125W SSB/CW (100W on 6m)
• Dual antenna switch (2 antenna inputs with independent memory banks)
• Advanced memory tuning with 4,200+ stored frequencies
• Near-instant tuning recall for previously used bands
• Auto or semi-auto tuning modes
• Built-in LED display for SWR, RF power, and status
• Supports coax-fed antenna systems
• Intelligent frequency sensing for automatic operation

Technical Specifications

• Frequency Range: 1.8 – 54 MHz
• Power Handling:
  • 1 – 125W SSB/CW
  • 100W on 6m band
  • 50W FM/Digital (solid-state radios)
• Impedance Range:
  • 6 – 1000 ohms (HF)
  • 16 – 150 ohms (6m)
• Memory Capacity: 4,200+ frequency-based memories
• Tuning Time:
  • Full tune: 0.5 – 6 seconds
  • Memory recall: ~0.2 seconds
• Antenna Ports: 2-position switch (dual antenna support)
• Display: LED bar graph (SWR, RF power, status)
• Power: 12V DC (radio or external supply depending on setup)

Compatible Antennas

• Dipole antennas
• Vertical antennas
• Inverted V antennas
• Beam antennas
• Coax-fed HF antenna systems
• With optional balun: long wire / ladder-line antennas

Ideal For

• Amateur radio HF operators
• Multi-antenna station setups
• Base station installations
• DX and contest operators
• Multi-band HF antenna systems
• Upgrade from internal radio tuners

Benefits

• Instantly switch between two antenna systems
• Fast automatic tuning with intelligent memory recall
• High-capacity memory system reduces tuning time
• Clear LED monitoring of SWR and power
• Reliable HF performance across all amateur bands
• Ideal for station optimisation and multi-antenna setups

Important Notes

• When used with radios such as IC-7300, FTDX10, or TS-890 in bypass mode, the tuner will pass 70MHz with minimal loss but will not actively tune on that frequency.