AY-840

The AY-840 is a professional-grade, high-gain UHF TETRA Yagi Antenna specifically engineered for high-performance directional communication in the 806–870 MHz frequency range. Delivering a powerful 13 dBi (11 dBd) gain, this antenna is an essential component for TETRA base stations, point-to-point links, and critical public safety networks. Constructed from 6063T6 ultra-corrosion-resistant architectural aluminum and protected by a tactical powder coating, the AY-840 is built to ensure peak signal integrity and mechanical survivability in the most demanding environmental conditions.

Design: Innovative Modern RF Construction

The AY-840 reflects a breakthrough in modern antenna engineering, featuring a unique feed system that acts as an integrated matching device. This proprietary design eliminates the need for a traditional folded dipole, resulting in significantly lower VSWR (better than 1.5:1) and increased radiation efficiency. With a focused horizontal beamwidth of 50 degrees and a vertical beamwidth of 40 degrees, the AY-840 concentrates RF energy with surgical precision. This directional focus, combined with a 16 dB front-to-back ratio, effectively isolates the desired signal while suppressing unwanted interference from the rear and sides.

Construction: Ruggedized for Tactical Survival

Engineered for ultimate structural longevity, the AY-840 is constructed using high-quality 6063T6 architectural anodized aluminum alloys for its radiating elements and support booms. The feed-point radiator is protected within a high-impact Nylon housing, specifically designed to withstand severe environmental stressors while preventing pattern distortion. The antenna is supplied in a pre-assembled condition with permanently fixed elements, ensuring electrical stability over time. Its small surface area and aerodynamic square-tube boom minimize wind resistance, making it ideal for high-wind installations rated up to 200 Km/Hr.

Integration: Marine-Grade Versatility

The AY-840 is a "field-ready" solution that comes factory-tuned for immediate deployment across the entire TETRA band. It includes specialized mounting hardware made of Type 316 marine-grade stainless steel, allowing for secure installation on either vertical or horizontal members up to 52mm in diameter. This versatility enables operators to switch between Vertical or Horizontal polarization to match mission requirements. Whether deployed in high-salinity coastal regions or extreme industrial environments, the AY-840 provides a reliable, high-power (150 Watts) directional link that requires zero field adjustments.

Technical Features

• Ultra-High 13 dBi (11 dBd) Gain: Optimized for long-range directional links and high-sensitivity TETRA reception.
• Complete 806–870 MHz Bandwidth: Provides full-band coverage for international public safety and trunked radio systems.
• Advanced Feed System: Integrated matching device ensures low VSWR and maximum power transfer efficiency.
• 6063T6 Aluminum Alloy Construction: Ultra-corrosion-resistant materials ensure a long service life in harsh climates.
• Marine Grade 316 Stainless Steel Hardware: High-quality fasteners and mounts prevent rust in saline coastal environments.
• Nylon Enclosed Radiator: Protects the critical feed point from moisture and environmental contaminants.
• Factory Tuned & Pre-Assembled: Eliminates the need for field tuning and ensures immediate tactical readiness.
• Vertical or Horizontal Polarization: Flexible mounting options to adapt to diverse network architectures.
• High Front-to-Back Ratio (16 dB): Enhances signal-to-noise ratio by rejecting off-axis interference.
• Tactical Powder Coating: Provides an additional layer of protection and a low-visibility signature.

Directional Link Optimization Guide: Extending TETRA Range with the AY-840

In critical communications, the AY-840 acts as a high-gain "force multiplier." By focusing RF energy into a directional beam, this 13 dBi antenna effectively triples the operating range compared to standard omni-directional dipoles, making it the definitive choice for point-to-point backbone links and "filling" coverage holes in remote sectors.

1. The Power of 13 dBi Gain: Overcoming Distance

In the RF world, a 6 dB increase in gain effectively doubles the distance of a usable signal in a line-of-sight environment.

• The High-Gain Advantage: By replacing a standard 2 dBi omni antenna with the AY-840’s 13 dBi gain, you achieve an 11 dB improvement. This massive increase in link budget allows the TETRA signal to penetrate deeper into buildings or reach remote outposts that were previously in "dead zones."
• Signal Concentration: Because the AY-840 uses a specialized feed instead of a folded dipole, it minimizes internal losses. Nearly 100% of your 150W transmitter power is converted into a focused beam, ensuring maximum signal-to-noise ratio (SNR) at the receiving end.

2. Interference Rejection & Front-to-Back Ratio

In high-density RF environments, "noise" from other transmitters can desensitize your TETRA receiver, causing dropped calls or data errors.

• The 16 dB Shield: The AY-840 features a 16 dB Front-to-Back ratio. This means the antenna is nearly 40 times less sensitive to signals coming from behind it than those in front.
• Tactical Isolation: By aiming the AY-840 at your target and "turning its back" to a known interference source (like a nearby cellular tower), you effectively clean up the RF environment. This isolation is critical for maintaining high-speed data throughput in modern TETRA networks.

3. Polarization Agility: Vertical vs. Horizontal

The AY-840 is supplied with marine-grade 316 stainless steel hardware that allows for mounting in either Vertical or Horizontal polarization.

• Vertical Polarization: Standard for most TETRA handhelds and mobile vehicle radios. Using vertical polarization ensures maximum compatibility with field units.
• Horizontal Polarization: Often used for fixed point-to-point backbone links between two towers. Horizontal polarization can help reduce interference from common vertically polarized man-made noise and improves link stability over long, flat stretches of land or water.

4. Minimizing Tower Load and Wind Resistance

High-gain antennas can often be heavy and bulky, putting excessive stress on tactical masts or high-altitude towers.

• Aerodynamic Design: The AY-840 uses a square-tube aluminum boom and thin 12.7mm elements. This minimal surface area results in a very low "Wind Surface Area."
• Survivability: Rated for 200 Km/Hr (125 MPH) winds, this antenna is designed to stay aligned and functional during severe storms, ensuring that emergency communications remain online when they are needed most.

Tactical Deployment Checklist

• Aiming Precision: With a 50-degree horizontal beamwidth, precise alignment is mandatory. A 20-degree error in aiming can result in a 3–6 dB loss of signal. Use a compass or GPS-based alignment tool to "zero-in" on the remote station.
• Cable Loss at 800 MHz: At TETRA frequencies, signal loss in the coaxial cable is a major "gain killer." Use high-quality LMR-400 or LMR-600 cables. A long run of thin RG-58 cable can easily waste 50% of your antenna's 13 dBi gain before the signal even reaches the elements.
• Nylon Housing Protection: The feed point is protected by a Nylon housing. Ensure this housing is pointed away from direct high-pressure water sources during cleaning to maintain its environmental seal.
• Mounting Rigidity: Ensure the marine-grade stainless steel U-bolts are tightened to a 52mm (2 inch) mast. Any "sway" in the mount will cause the narrow 40-degree vertical beam to "flutter," leading to intermittent signal drops during high winds.