AS-500-2000

The AS-500-2000 is a professional-grade Cavity Backed Circular Polarized Spiral Antenna engineered for wideband directional performance across the 500–2000 MHz spectrum. This dual-arm Archimedean spiral is a frequency-independent solution, specifically designed to handle critical L-band and UHF communications. Whether utilized for Signal Intelligence (SIGINT), Electronic Countermeasures (ECM), or high-speed telemetry, the AS-500-2000 provides the circular polarization (LHCP or RHCP) necessary to maintain link stability in environments prone to multi-path fading and signal rotation.

Design: Wideband Directional Dominance

The AS-500-2000 is meticulously crafted to deliver consistent, high-efficiency performance throughout its entire frequency spread. By utilizing an extended coaxial stubs technique, the antenna maintains a typical 3 dBi gain while preserving a wide 60–80 degree half-power beamwidth. This wide-angle, directional radiation pattern allows for effective sector scanning and monitoring without the signal drop-off common in conventional narrow-band antennas. Its cavity-backed architecture ensures that all RF energy is focused forward, providing high immunity to noise and a superior front-to-back ratio for precision surveillance and direction-finding (DF) tasks.

Durability: Ruggedized MIL-SPEC Engineering

Built for survival in the most punishing tactical environments, the AS-500-2000 is constructed from 6063T6 ultra-corrosion-resistant architectural anodized aluminum alloy. The internal radiating copper strips are protected by a ruggedized fiberglass or ABS front enclosure, ensuring maximum RF transparency and mechanical robustness. The unit is finished with a protective powder coating, rated for winds up to 170 Km/Hr, and built to operate in temperatures from -30°C to +60°C, making it suitable for permanent outdoor installations, naval platforms, or high-speed airborne mounting.

Efficiency: Circular Polarization for Reliable Links

A standout feature of the AS-500-2000 is its use of Circular Polarization, available in Left Hand (LHCP) or Right Hand (RHCP) configurations. Circular polarization is essential in contested RF environments where signal "spin" or multi-path reflections (common in urban or mountainous terrain) cause traditional linear antennas to suffer from polarization mismatch and fading. With a power handling capacity of 50 Watts, this spiral antenna offers significantly higher efficiency than standard "rubber duck" or omni-directional antennas, providing a "dead-solid" link for wideband monitoring and high-speed data telemetry.

Technical Features

• Ultra-Broadband 0.5–2 GHz Coverage: Continuous operation from 500 MHz to 2000 MHz in a single directional unit.
• Dual Arm Archimedean Design: Frequency-independent performance ensures stable gain and VSWR across the entire band.
• Circular Polarization (LHCP/RHCP): Minimizes signal fading and multi-path interference; ideal for airborne, satellite, and drone links.
• Extended Coaxial Stubs Technique: Provides a constant 3 dBi gain while maintaining wide horizontal and vertical beamwidths.
• Cavity Backed Shielding: Anodized aluminum cavity ensures high immunity to noise and eliminates unwanted rear radiation.
• Architectural Grade Materials: Built from 6063T6 aluminum alloy and high-strength fiberglass for ultimate structural integrity.
• Compact & Lightweight: Weighing only 2 Kgs with a low-profile 90mm height, it is ideal for man-portable and airborne deployments.
• Weatherproof Enclosure: Powder-coated finish and protective front cover ensure 24/7 reliability in severe environmental conditions.
• Integrated Matching Circuit: Housed inside the main body of the antenna for a streamlined, durable design.
• Zero Field Tuning: Factory-calibrated for immediate "plug-and-play" deployment in receiving or transmitting roles.

SIGINT & Direction Finding Guide: Precision Signal Acquisition with AS-500-2000

In Signal Intelligence (SIGINT) and Electronic Countermeasures (ECM), capturing a signal on the first transmission is critical. The AS-500-2000 Archimedean spiral antenna is a "frequency-independent" instrument specifically engineered to solve the two primary obstacles in tactical RF monitoring: Polarization Mismatch and Multi-path Fading.

1. The Power of Circular Polarization (CP)

Most tactical radios, cellular transmitters, and lower-band telemetry links use linear antennas (Vertical or Horizontal). However, when these signals reflect off the ground, buildings, or dense foliage, their polarization "flips" or rotates unpredictably.

• The Problem: If you use a standard vertical antenna to receive a signal that has rotated toward a horizontal plane, you can experience a signal loss of up to 20 dB (99%).
• The AS-500-2000 Advantage: Because this antenna is Circularly Polarized (LHCP or RHCP), it captures energy from any linear orientation. Whether the target signal is vertical, horizontal, or slanted, the AS-500-2000 intercepts it with minimal loss. This is vital for Direction Finding (DF), where a steady, non-fading signal is required to calculate an accurate line-of-bearing.

2. Archimedean Spiral: Frequency Independence

Traditional wideband antennas (like Log Periodics) have specific "sweet spots" where they perform best. Outside of those narrow bands, their gain and radiation patterns can fluctuate, creating "blind spots" in your surveillance.

• The Design: An Archimedean spiral is unique because its "active region"—the portion of the antenna actually radiating—moves along the spiral arms as the frequency changes.
• The Tactical Benefit: From 500 MHz to 2000 MHz, the AS-500-2000 maintains a nearly constant impedance and radiation pattern. This allows your SIGINT receiver to sweep the spectrum without experiencing gain drops. You receive the same 3 dBi gain whether you are hunting for a 500 MHz tactical radio or a 1.2 GHz GPS/GNSS signal.

3. Cavity Backing for Directional Accuracy

A spiral antenna naturally radiates in two directions (forward and backward). In a SIGINT application, you only want to intercept signals from the direction the antenna is facing to maintain geographical context.

• The Shielding: The AS-500-2000 is Cavity Backed with 6063T6 aluminum. This reflects the backward-traveling energy forward, effectively doubling the gain and creating a clean 60–80 degree beamwidth.
• ECM Application: When used for jamming, the cavity ensures that RF energy (up to 50 Watts) is directed strictly toward the threat, protecting the operators and friendly electronics located behind the antenna from high-intensity RF exposure.

4. Wide-Angle Monitoring for Rapid Discovery

High-gain dish antennas are like looking through a telescope; they are excellent for long range but difficult to use when searching for an unknown signal source.

• The Search Advantage: With a 60–80 degree beamwidth, the AS-500-2000 acts like a "floodlight." It monitors a massive sector of the horizon simultaneously. In a Direction Finding array (typically using 4 spirals), this allows for instantaneous 360-degree coverage, identifying the location of a transmitter the moment it keys up.

Tactical SIGINT Deployment Checklist

• Polarization Matching: Ensure your entire array uses the same polarization (all LHCP or all RHCP). For most satellite and drone monitoring applications in the 500-2000 MHz range, LHCP is the preferred standard for multi-path rejection.
• Height & Obstruction: While 500 MHz signals have some "bend" over terrain, 2000 MHz signals are strictly "Line-of-Sight." Mount the AS-500-2000 as high as possible, using the fiberglass or ABS cover to protect the internal copper elements from dust and moisture.
• Cable Selection: At 2000 MHz (2 GHz), signal loss in the cable becomes a factor. Keep the coaxial run between the antenna and the receiver as short as possible, and use high-quality LMR-400 cables to ensure the 3 dBi gain is preserved at the receiver input.
• Mounting Stability: Use the supplied hardware for 19–25.4mm poles. A vibrating or "fluttering" mount can introduce phase errors into your SIGINT data, which significantly degrades the accuracy of your Direction Finding location fix.