AS-800-4000

The AS-800-4000 is a state-of-the-art Dual Arm Archimedean Cavity Backed Spiral Antenna engineered for ultra-wideband performance from 800 MHz to 4000 MHz. This frequency-independent antenna is a critical component for high-stakes missions requiring Circular Polarization (LHCP or RHCP) to overcome multi-path interference and signal fading. Designed for directional transmission and reception, the AS-800-4000 is the primary choice for Electronic Countermeasures (ECM), Signal Intelligence (SIGINT), and advanced direction-finding (DF) applications across terrestrial and airborne platforms.

Design: Ultra-Broadband Directional Precision

The AS-800-4000 is meticulously crafted to maintain consistent performance across a massive frequency spread. By utilizing an extended coaxial stubs technique, the antenna provides a constant 3 to 6 dBi gain while preserving a wide 60–80 degree half-power beamwidth. This wide-angle, directional radiation pattern makes it exceptionally effective for scanning and monitoring broad sectors without losing signal sensitivity. Its cavity-backed design ensures that radiation is directed forward, significantly reducing back-lobe interference and improving the front-to-back ratio for precision SIGINT and telemetry tasks.

Durability: Ruggedized Architectural Grade Construction

Engineered for severe environmental survival, the AS-800-4000 is constructed from 6063T6 ultra-corrosion-resistant architectural anodized aluminum alloy. The radiating copper strips are sealed within this aluminum cavity and protected by a high-strength fiberglass front enclosure, ensuring the system remains immune to external noise and harsh weather. The entire unit is finished with a durable powder coating, rated for winds up to 170 Km/Hr, and built to operate in temperatures ranging from -30°C to +60°C, making it suitable for permanent outdoor installation or high-speed airborne mounting.

Efficiency: Circular Polarization for Contested RF Environments

A standout feature of the AS-800-4000 is its use of Circular Polarization, available in either Left Hand (LHCP) or Right Hand (RHCP) configurations. Circular polarization is vital in environments where signal "spin" or multi-path reflections (common in urban or mountainous terrain) would cause traditional linear antennas to fail. With a power handling capacity of 150 Watts, this spiral antenna delivers significantly higher efficiency than conventional rubber duck or whip antennas, providing a "dead-solid" link for wideband surveillance and high-speed data telemetry.

Technical Features

• Massive Frequency Range: Continuous, wideband operation from 800 MHz to 4000 MHz in a single directional unit.
• Dual Arm Archimedean Design: Frequency-independent architecture ensures stable gain and VSWR across the entire band.
• Circular Polarization (LHCP/RHCP): Minimizes signal fading and multi-path interference; ideal for airborne and satellite links.
• Extended Coaxial Stubs Technique: Provides a constant 3+ dBi gain while maintaining wide horizontal and vertical beamwidths.
• High Power Handling: Capable of managing up to 150 Watts of RF power for transmission and ECM applications.
• Cavity Backed Shielding: Aluminum cavity housing ensures high immunity to noise and eliminates unwanted rear radiation.
• Aviation-Grade Materials: Built from 6063T6 aluminum and high-strength fiberglass for ultimate structural integrity.
• Versatile Mounting Hardware: Supplied with specialized brackets for vertical poles (19–25.4mm), with customized options available.
• Compact & Lightweight: Weighing only 2 Kgs with a 250mm diameter, it is suitable for man-portable and airborne deployments.
• Weatherproof Enclosure: Powder-coated finish and fiberglass cover ensure 24/7 reliability in severe environmental conditions.

SIGINT & Direction Finding Guide: Precision Signal Acquisition with AS-800-4000

In Signal Intelligence (SIGINT) and Electronic Countermeasures (ECM), the ability to intercept a signal on the first pass is the difference between mission success and failure. The AS-800-4000 Archimedean spiral antenna is a "frequency-independent" tool designed to solve the two biggest problems in tactical RF monitoring: Polarization Mismatch and Multi-path Fading.

1. The Power of Circular Polarization (CP)

Most tactical radios and drones use linear antennas (Vertical or Horizontal). When a signal reflects off a building, a hill, or the ground, its polarization "flips" or rotates.

• The Problem: If you use a vertical antenna to receive a signal that has rotated to horizontal, you can lose up to 20 dB (99%) of the signal strength.
• The AS-800-4000 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-800-4000 intercepts it with minimal loss. This is critical for Direction Finding (DF), where you need a steady signal to calculate a precise line-of-bearing.

2. Archimedean Spiral: Frequency Independence

Traditional antennas (like Yagis or Log Periodics) have "sweet spots" where they work best. Outside of those narrow bands, their performance drops.

• The Design: An Archimedean spiral is unique because its active region moves along the spiral arms as the frequency changes.
• The Tactical Benefit: From 800 MHz to 4000 MHz, the AS-800-4000 maintains a nearly constant impedance and radiation pattern. This means your SIGINT receiver won't see "blind spots" as it sweeps through the spectrum. You get the same 3–6 dBi gain whether you are hunting for a 900 MHz GSM signal or a 2.4 GHz Wi-Fi, Bluetooth and ISM communication.

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 see what is in front of you.

• The Shielding: The AS-800-4000 is Cavity Backed with 6063T6 aluminum. This reflects the backward energy forward, doubling the effective gain and creating a clean 60–80 degree beamwidth.
• ECM Application: When used for jamming, the cavity ensures that high-power RF (up to 150 Watts) is directed strictly toward the target, protecting the operators and friendly equipment located behind the antenna from high-intensity RF exposure.

4. Wide-Angle Monitoring for Rapid Discovery

Narrow-beam antennas (like high-gain dishes) are like looking through a straw; they are great once you find the target, but terrible for searching.

• The Search Advantage: With a 60–80 degree beamwidth, the AS-800-4000 acts like a "floodlight." It covers a massive sector of the horizon at once. In a Direction Finding array (using 4 or 6 spirals), this allows for instantaneous 360-degree coverage, identifying the location of a threat the moment it keys its transmitter.

Tactical SIGINT Deployment Checklist

• Polarization Matching: Ensure your array uses the same polarization (all LHCP or all RHCP). For most drone and satellite monitoring, LHCP is the standard for multi-path rejection.
• Height & Obstruction: At 4 GHz, the signal is "Line-of-Sight." Even a small tree branch can block the signal. Mount the AS-800-4000 as high as possible, using the fiberglass cover to protect the internal copper elements from wind-borne debris.
• Cable Loss at 4 GHz: At the upper end of the 800–4000 MHz band, signal loss in the cable is extreme. Keep the coaxial run between the antenna and the receiver as short as possible, and use high-quality LMR-400 or LMR-600 cables to preserve the 6 dBi gain.
• Mounting Stability: Use the specialized hardware for a 19–25.4mm pole. A loose mount will cause the antenna to "flutter" in the wind, which introduces phase noise into your SIGINT data, making it harder to get an accurate location fix.