SD6-250
UHF High Gain Stacked Dipole Array
| Model | Product Description | Frequency | Gain | Download | Enquiry | |
|---|---|---|---|---|---|---|
| SD6-250 | UHF High Gain Stacked Dipole Array | 220-290 MHz | 6 dBd. |  |  |  |
The SD6-250 is a high-performance VHF stacked dipole array designed for the 220–290 MHz frequency range. Featuring four vertically stacked folded dipoles, this antenna is engineered for high-density radio sites that require reliable, long-range coverage. With its high power handling and "null-fill" characteristics, it serves as an ideal base station antenna for repeater and paging systems.
Field-Adjustable Radiation Patterns
The SD6-250 offers exceptional versatility through its adjustable configuration. When the four dipoles are arranged 90° apart around the central mast, a 6 dBd omni-directional pattern is produced for 360 degrees coverage. Alternatively, aligning all four dipoles in a single direction creates a 9 dBd offset pattern, focusing energy to bridge longer distances. These changes can be made in the field using common hand tools, allowing for real-time site optimization.
Robust Construction and Logistics
Constructed from high-strength 6063T6 aluminum, the antenna is built to withstand extreme environmental stress, including wind speeds up to 200 Km/Hr. The 3.6-meter overall length is designed for logistics efficiency, shipping in two sections of 1.8 meters each. For maximum protection, the phasing harness is sealed with heat-shrink tubing to ensure total waterproofing, while the folded dipoles are manufactured from durable 12.7 mm aluminum tubing.
Operational Resilience
Designed for mission-critical infrastructure, the SD6-250 handles up to 500 Watts of RF power. It features a wide 20 MHz bandwidth with a VSWR of better than 1.5:1, ensuring efficient power transfer. For electrical safety, the antenna operates at direct D.C. ground, providing an integrated discharge path to shield connected radio equipment from lightning-induced transients and atmospheric noise.
Detailed Technical Features
- Dual-Gain Modes: Switchable between 6 dBd (Omni) and 9 dBd (Offset) configurations.
- Vertical Focus: 18-degree half-power vertical beam-width for efficient horizon-targeted propagation.
- High Power Capacity: Supports continuous RF power handling of up to 500 Watts.
- Phasing Integrity: Center-fed phasing harness ensures all dipoles are fed in phase for maximum gain.
- Low Noise Design: Engineered to minimize interference at highly populated radio sites.
Detailed Mechanical Features
- Array Length: 3.6-meter overall height, collapsible to 1.8 meters for easy shipping.
- Materials: 51 mm O.D. aluminum support pipe with 12.7 mm O.D. folded dipoles.
- Mounting Versatility: Supplied with top mounting hardware; optional 1.35-meter side-mount arms available.
- Elite Fasteners: All mounting hardware and fasteners are made of Marine Grade Stainless Steel.
- Gross Weight: Robust yet manageable at 18 Kgs.
Detailed Environmental Features
- Wind Survival: Rated for extreme stability in winds up to 200 Km/Hr.
- Thermal Hardening: Fully operational from -30°C to +70°C.
- Moisture Protection: Heat-shrink sealed harness for consistent performance in high-humidity (0-95% RH) zones.
- Lightning Shielding: Direct D.C. ground path for equipment protection.
Key Advantages
- Tactical Versatility: The ability to switch between omni and offset patterns in the field provides a significant logistical advantage.
- High Reliability: Anodized aluminum and stainless steel components ensure a long service life in corrosive or salty environments.
- Logistical Efficiency: Two-section shipping design reduces transport costs and simplifies handling.
Primary Applications
- Repeater Base Stations: High-gain backbone for regional VHF repeater networks.
- Paging Sites: Reliable, high-power signal distribution for mission-critical paging infrastructure.
- Populated Radio Sites: Designed to maintain low-noise performance in crowded RF environments.
Tactical Communication: Ideal for rapid deployment where pattern flexibility is required.
| Feature | Specification | Tactical Benefit |
|---|---|---|
| Gain | 6 dBd (Omni) / 9 dBd (Offset) | Adaptable coverage for different site requirements. |
| Wind Rating | 200 Km/Hr | Stays operational in hurricane-force conditions. |
| Power Handling | 500 Watts | Supports high-power multi-channel transmitters. |
| Mounting | Side or Top Mount | Flexible installation on various tower types. |
Design Features: The SD6-250 ultra high performance VHF band stacked dipole array is designed for use with highly populated radio sites requiring long haul omni-directional coverage. The SD6-250 is heavy duty stacked dipole array features, wide bandwidth, high gain, high power handling capacity, low VSWR, low noise performance and null filling coverage with omni-directional characteristics. This stacked dipole array maintains constant 6dBd gain and VSWR over its 20 MHz bandwidth, making it highly suitable as base station antennas for repeater, paging and any other multi-channel communication systems. The radiation pattern can be changed in the field by use of common hand tools. The Vertical stacking distance is factory adjusted for highest possible efficiency. Specially designed center fed phasing harness ensures equal and in phase signal distribution to all the four dipoles. The SD6-250 high gain stacked dipole array operates at D.C. ground for protection against lightning.
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