AS-300-6000 Cavity Backed Spiral Antenna | 300-6000 MHz SIGINT/ECM
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AS-300-6000

Cavity Backed Dual Arm Spiral Antenna

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AS-300-6000Cavity Backed Dual Arm Spiral Antenna300-6000MHz3~6 dBicDownload DatasheetDownload ManualPost Enquiry

The AS-300-6000 is a premier, ultra-wideband Dual Arm Archimedean Cavity Backed Spiral Antenna designed for total spectrum dominance from 300 MHz to 6000 MHz. This frequency-independent antenna provides a single-unit solution for directional transmission and reception across the UHF, L, S, and C bands. Engineered for Circular Polarization (LHCP or RHCP), it is an essential asset for high-stakes missions including Signal Intelligence (SIGINT), Electronic Countermeasures (ECM), and Direction Finding (DF), where mitigating multi-path interference and signal fading is critical for tactical success.

Design: Wideband Directional Precision

The AS-300-6000 is meticulously engineered to maintain consistent RF performance across a massive 5.7 GHz bandwidth. Utilizing an extended coaxial stubs technique, the antenna delivers a stable 3 to 6 dBi gain while maintaining a wide 60–80 degree half-power beamwidth. This wide-angle directional coverage is essential for scanning large sectors without the sensitivity loss typical of narrower antennas. The cavity-backed architecture ensures all RF energy is focused forward, providing high immunity to noise and a superior front-to-back ratio, which is vital for precision surveillance and persistent signal monitoring.

Durability: Ruggedized Architectural Grade Engineering

Built for survival in the most punishing outdoor and tactical environments, the AS-300-6000 is constructed from 6063T6 ultra-corrosion-resistant architectural anodized aluminum alloy. The radiating copper strips are protected by a high-strength fiberglass front enclosure, ensuring maximum RF transparency and mechanical robustness. The unit is finished with a protective powder coating, rated for extreme winds up to 200 Km/Hr, and built to operate in temperatures from -30°C to +70°C, making it suitable for permanent mast installations, naval platforms, or high-speed airborne mounting.

Efficiency: Circular Polarization for Contested RF Environments

A core advantage of the AS-300-6000 is its Circular Polarization, available in Left Hand (LHCP) or Right Hand (RHCP) configurations. Circular polarization is critical in urban or mountainous terrain where multi-path reflections cause linear signals to "flip" and fade. With a power handling capacity of 150 Watts, this spiral antenna operates with significantly higher efficiency than traditional wideband whip antennas. It is the definitive choice for high-speed data telemetry and high-power electronic warfare missions where maintaining a "dead-solid" link is non-negotiable.

 

Technical Features

  • Ultra-Broadband 0.3–6 GHz Coverage: Continuous operation from 300 MHz to 6000 MHz in a single, high-performance directional unit.
  • Dual Arm Archimedean Design: Frequency-independent performance ensures stable gain and VSWR (3:1) across the entire spectrum.
  • Circular Polarization (LHCP/RHCP): Eliminates signal fading and multi-path mismatch; ideal for airborne and satellite tracking.
  • Extended Coaxial Stubs Technique: Provides constant 3+ dBi gain while maintaining wide horizontal and vertical beamwidths.
  • High Power Capacity: Manages up to 150 Watts of RF power, supporting high-intensity ECM and jamming applications.
  • Cavity Backed Shielding: Anodized aluminum cavity ensures maximum noise immunity and forward-focused radiation.
  • Versatile Mounting Hardware: Supplied with specialized brackets for mast mounting on vertical poles (38–52mm diameter).
  • Architectural Grade Materials: Constructed from 6063T6 aluminum alloy and high-strength fiberglass for ultimate structural longevity.
  • Large Aperture Efficiency: Approximately 550mm diameter optimized for high sensitivity at lower frequencies (300 MHz).
  • 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-300-6000

In Signal Intelligence (SIGINT) and Electronic Countermeasures (ECM), the ability to capture a signal on the first transmission is the difference between mission success and tactical failure. The AS-300-6000 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 low-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-300-6000 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-300-6000 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 300 MHz to 6000 MHz, the AS-300-6000 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 3–6 dBi gain whether you are hunting for a 300 MHz military radio or a 5.8 GHz drone video downlink.

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-300-6000 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 150 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-300-6000 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 Consistency: Ensure your entire array uses the same polarization (all LHCP or all RHCP). For most satellite and drone monitoring applications, LHCP is the preferred standard for multi-path rejection.
  • Height & Obstruction: While 300 MHz signals have some "bend" over terrain, 6000 MHz signals are strictly "Line-of-Sight." Mount the AS-300-6000 as high as possible, using the fiberglass cover to protect the internal copper elements from dust and moisture.
  • Cable Selection: At 6000 MHz (6 GHz), 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-600 cables to ensure the 6 dBi gain is preserved at the receiver input.
  • Mounting Stability: Use the supplied hardware for 38–52mm 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.

Design Features Features The cavity backed dual arm archimedean spiral antenna use 6063T6 ultra corrosion resistant architectural anodized aluminum alloy and designed to provide wideband directional transmission/reception of radio signals from 300-6000 MHz bands. The antenna is supplied with powder coating finish to protect the antenna further from severe environmental conditions. Both left hand circular polarization (LHCP) and right hand circular polarization (RHCP) are available. The cavity backed dual arm archimedean spiral antenna is a frequency independent antenna and this spiral antenna is weather protected suitable for outdoors use in applications requiring circularly polarized RF radiations. The AS-300-6000 uses extended coaxial stubs technique to provide constant 3+ dBi gain over entire 300-6000 MHz frequency band while maintaining the wider beam-width. This cavity backed spiral antenna is highly suitable for transmission, reception, monitoring, scanning, ECM, surveillance, signal intelligence (SIGINT), direction finding (DF), telemetry and airborne applications due to its ultra broad band design feature.

Constructions The spiral antenna is sealed in an aluminum cavity and is highly immune to noise. Matching circuit of spiral antenna is housed inside the main body of the antenna. A special mounting hardware to mount the spiral antenna on vertical pole having outer diameter of 38-52mm (1.5"-2"). Higher diameter mounting including any customized mounting can be supplied on request. Spiral antenna N-Female termination is fixed on top of the antenna body for easy connectivity. Other termination can be supplied on request. The AS-300-6000 spiral antenna is light weight, broadband and rugged spiral antennas, supplied with Nylon plastic cover to protect the antenna from environment. The spiral antenna is designed to perform with much higher efficiency than conventional rubber duck antenna.

 

Electrical Specifications:
Frequency Range300-6000 MHz
Gain3~6 dBic
Bandwidth300-6000MHz
PolarizationCircular - LHCP or RHCP
Input Impedance50 Ohms
Radiation PatternDirectional
Horizontal Beamwidth -Half Power Points60-80 Degrees
Front to Back Ratio18 dB.
VSWR - Equal To or Better Then2.5:1
RF Power Handling Capacity150 Watts
Input TerminationN-Female or SMA-Female


 

Mechanical Specifications:
Antenna MaterialsAluminum & Copper
Mounting Hardware -MaterialsMarine Grade Stainless Steel
Wind Rating170 Km/Hr.
Overall Length550mm x 150mm
Shipping Length600mm x 180mm
Housing MaterialAluminum Enclosure
Radiating MaterialCopper
Insulator MaterialNylon
Maximum Mount Pipe Diameter38-52mm (1.5-2")
Gross Weight5 Kgs.


 

Environmental Specifications:
Operating Temperature(-)30 to +60 Degrees Celsius
Storage Temperature(-)40 to +70 Degrees Celsius
Humidity0 to 95% RH