HL-225-400

The HL-225-400 is a professional-grade, circular polarized helical antenna designed for the UHF Military Aviation Band (225–400 MHz). By utilizing advanced helical technology, it provides superior signal penetration and multipath interference rejection, making it the premier choice for satellite tracking, terrestrial links, and ground-to-air communications.

Circular Polarized Performance

The HL-225-400 delivers a typical gain of 10 dBic using Circular Polarization Antenna Technology, available in both Right-Hand (RHCP) and Left-Hand (LHCP) models. This polarization is a strategic advantage for aviation and satellite links, as it significantly reduces signal fading caused by multipath interference and allows for better penetration through atmospheric obstructions. The antenna features a focused 50-degree beam-width in both horizontal and vertical planes, providing a symmetrical radiation pattern that is ideal for tracking mobile assets across the 360-degree azimuth and 90-degree elevation ranges.

Rugged Construction and Durability

Engineered for survival in extreme environments, the HL-225-400 is enclosed in a high-strength fiberglass radome. This cylindrical enclosure protects the internal high-purity copper radiating elements from ice formation, acid rain, and corrosive gases while maintaining a low-wind profile. The reflector is constructed from 6061T6 architectural-grade aluminum alloy, ensuring structural rigidity without unnecessary weight. With a wind rating of 200 Km/Hr, the antenna is designed to stay operational during severe storm events, and its all-weather construction ensures a long service life in both coastal and desert theaters.

Operational and Tactical Efficiency

Despite its high-performance capabilities, the HL-225-400 is more compact than conventional Yagi antennas of similar gain, offering a more efficient footprint for crowded mast installations. It supports a high RF power capacity of 500 Watts, making it suitable for intensive transmission tasks. For missions requiring even greater reach, the antenna is designed for array formation, allowing it to be QUAD or DUAL-stacked with a specialized phasing harness. This flexibility, combined with its "fit-and-forget" durability, makes it an exceptionally efficient tool for modern military aeronautical ATC sites.

Detailed Technical Features

• Advanced Circular Polarization: Delivers 10 dBic gain, providing superior signal stability compared to linear antennas by minimizing Faraday rotation and multipath effects.
• Optimized Beam Geometry: Symmetrical 50° horizontal and vertical beam-widths ensure consistent signal capture for tracking applications.
• Broadband Efficiency: Provides high performance across the 225–400 MHz range, specifically optimized for the 240–380 MHz spectrum.
• High Front-to-Back Ratio: Features a 16 dB F/B ratio, isolating the intended signal and reducing interference from rearward sources.
• High Power Handling: Supports 500 Watts of continuous power for high-intensity links.
• D.C. Grounded Design: Integrated lightning protection and static discharge path for equipment safety.

Detailed Mechanical Features

• Copper Radiating Element: High-conductivity copper helix for maximum RF efficiency.
• Fiberglass Radome: 260 mm diameter protective enclosure, RF transparent and UV resistant.
• Structural Reflector: 400 x 400 mm 6063T6 aluminum backplane for high-precision signal reflection.
• Compact Profile: Overall length of 1300 mm (1.3 meters), significantly smaller than linear arrays of equivalent gain.
• Stainless Steel Hardware: All mounting components are corrosion-resistant stainless steel.
• Mounting Versatility: Designed for 52 mm (2-inch) diameter masts.

Detailed Environmental Features

• Severe Temperature Range: Operational from -30°C to +70°C and storage rated to +80°C.
• Ice & Wind Resilience: Cylindrical radome minimizes ice accumulation and provides a low wind load (rated for 200 Km/Hr).
• Humidity Tolerance: Certified for 0 to 95% RH, suitable for tropical and high-humidity oceanic deployments.

Key Advantages

• Multipath Rejection: Circular polarization allows the signal to "spin" through obstructions, providing a much more stable link for ground-to-air and satellite communication.
• Steerable Alignment: Highly compatible with dual-plane steering mounts for full 360° Azimuth and 90° Elevation tracking.
• Radome Protected: The fiberglass enclosure ensures the antenna's electrical properties remain constant, even in heavy snow or salt-fog.

Primary Applications

• Satellite Communication (SATCOM): Ideal for tracking UHF satellites in Low Earth Orbit (LEO) or geostationary positions.
• Military Air Traffic Control (ATC): Providing a stable link for aircraft that may be changing orientation and polarization relative to the ground station.
• Tactical Jamming & EW: Concentrating circular polarized energy to disrupt enemy aeronautical and satellite-based links.

• Ground-to-Air Signal Monitoring: Sensitive directional capture of aircraft transmissions in the 225-400 MHz band.