SD9-150
VHF High Gain Stacked Dipole Array
| Model | Product Description | Frequency | Gain | Download | Enquiry | |
|---|---|---|---|---|---|---|
| SD9-150 | VHF High Gain Stacked Dipole Array | 135-175 MHz | 9 dBd |  |  |  |
The SD9-150 is an ultra-high-performance VHF stacked dipole array designed for the critical 136–174 MHz band. Featuring eight vertically stacked folded dipoles, this antenna is the gold standard for high-density radio sites requiring long-haul omni-directional coverage. Its massive aperture and high power handling make it an ideal backbone for regional repeaters, paging networks, and multi-channel communication hubs.
Precision Engineering for Coverage
The SD9-150 offers exceptional gain versatility. In its standard configuration, it provides a 9 dBd omni-directional pattern for 360 degrees coverage. For missions requiring specialized directional focus, the array can be field-adjusted to produce a 12 dBd offset pattern. A specially designed center-fed phasing harness ensures that signal distribution remains equal and in-phase across all eight dipoles, maintaining a razor-sharp 9-degree vertical beam-width to maximize horizon-level propagation.
Industrial-Grade Construction
Built from 6063T6 architectural-grade anodized aluminum, the SD9-150 is designed for permanent installation in punishing environments. Each dipole end and cable connection is sealed in high-strength epoxy to prevent moisture ingress and provide structural rigidity. To overcome the logistical challenges of its 12-meter (39.3 feet) height, the central mast is shipped in four manageable 3-meter sections, allowing for easier transport to remote tower sites.
Operational Resilience & Safety
Designed for "always-on" infrastructure, the antenna supports up to 500 Watts of RF power with a VSWR of better than 1.5:1 over its 10 MHz operating window. Protection is a core feature; the N-Female termination is sealed in flame-retardant heat-shrink tubing for waterproofing, and the entire array operates at direct D.C. ground. This provides a dedicated low-resistance path for lightning strikes, shielding sensitive base station electronics from damage during storms.
Detailed Technical Features
- Elite Gain Performance: Delivers a consistent 9 dBd (11.1 dBi) gain in an omni-directional configuration. This allows for massive signal penetration over vast geographical areas, overcoming path loss in rural or mountainous terrain.
- Vertical Beam Precision: Features a razor-sharp 9-degree vertical beam-width. By concentrating RF energy toward the horizon and away from the sky or the ground immediately beneath the tower, the antenna maximizes "long-haul" reach.
- Field-Adjustable Pattern:
- Omni-Directional: Arranging dipoles around the mast provides $360^{\circ}$ coverage.
- Offset Directional: Aligning dipoles collinearly provides 12 dBd (14.1 dBi) gain, focusing energy toward a specific sector.
- Phasing Integrity: Utilizes a specialized center-fed phasing harness. This ensures that all eight dipoles receive an equal and in-phase signal, preventing pattern distortion and maintaining peak gain across its 10 MHz bandwidth.
- Null-Fill Engineering: Designed to provide consistent coverage even in the "null" zones that typically occur close to the base of high-gain antennas, ensuring near-field users are not "overshot" by the signal.
Detailed Mechanical Features
- Massive Structural Aperture: The 12-meter (39.3-foot) overall length provides a large capture area for receiving weak signals while offering a high-profile transmission platform.
- Logistical Sectional Design: The central mast is manufactured in four interlocking 3-meter sections. This allows a nearly 40-foot antenna to be shipped via standard freight and transported to remote mountain-top sites where a single-piece mast would be impossible to deliver.
- Industrial-Grade Materials:
- Radiators: Folded dipoles are constructed from 12.7 mm high-strength aluminum tubing.
- Support Mast: Features a heavy-duty 51 mm outer diameter 6063T6 aluminum framework.
- Weather Sealing: The dipole ends and cable connections are sealed in high-impact epoxy, providing structural rigidity and preventing internal oxidation.
- Elite Hardware: All mounting fasteners and brackets are made of Marine Grade Stainless Steel, ensuring the array can be serviced or adjusted even after years of exposure to the elements.
Detailed Environmental Features
- Hurricane Resilience: Despite its extreme height, the narrow profile of the dipoles and the strength of the 6063T6 aluminum mast provide a wind rating of 180 Km/Hr (112 MPH).
- Integrated Lightning Protection: The entire antenna structure operates at direct D.C. ground. The aluminum tubular boom provides a low-resistance path to discharge lightning strikes directly to the tower ground, shielding the connected radio equipment.
- Waterproofing: The RF input (N-Female termination) is protected by flame-retardant heat-shrinking tubing, creating a hermetic seal against driving rain and ice.
- Extreme Thermal Window:
- Operational: -30°C to +70°C.
- Humidity: Rated for 0 to 95% RH, making it suitable for both arid desert and humid tropical environments.
Technical Summary Comparison
| Feature | Specification | Tactical Benefit |
|---|---|---|
| Gain | 9 dBd Omni / 12 dBd Offset | Versatile coverage for regional or sectorized needs. |
| Vertical Beam | 9 Degrees | Maximizes horizon distance; reduces signal waste. |
| Wind Rating | 180 Km/Hr | Stays operational during severe weather events. |
| Height | 12 Meters (39.3') | Strategic height for peak signal propagation. |
| Construction | Sectional (4 x 3m) | High portability for such a large array. |
Key Advantages
- Strategic Pattern Versatility: The primary advantage is the ability to shift between a 9 dBd omni-directional pattern for $360^{\circ}$ regional coverage and a 12 dBd offset pattern for targeted sector coverage. This allows the antenna to adapt to changing network requirements without a complete hardware replacement.
- Elite Vertical Directivity: With a razor-sharp 9-degree vertical beam-width, the antenna focuses RF energy toward the horizon. This minimizes "sky-waste" and ground-reflection interference, ensuring the maximum possible link distance for a terrestrial VHF system.
- Null-Fill Coverage: Unlike many high-gain antennas that suffer from signal "dead zones" directly beneath the tower, the SD9-150 is engineered with null-fill characteristics to ensure consistent signal strength for users located in the near-field.
- Low-Noise Performance: Designed for highly populated radio sites, the array maintains a stable VSWR (1.5:1) and low-noise profile, which is critical when multiple transmitters and receivers are co-located on the same tower.
- High Power Reserve: Rated for 500 Watts, this antenna can easily handle high-power paging transmitters or multiple combined repeater channels simultaneously.
Strategic Benefits
- Reduced Infrastructure Density: By providing 9–12 dBd of gain, the SD9-150 allows for longer-distance hops. This can reduce the total number of repeater sites required to cover a specific geographic region, lowering both CAPEX and ongoing land-lease costs.
- Logistical Efficiency: Despite its 12-meter height, the four-section mast design allows for significantly lower shipping costs and the ability to transport the antenna to remote mountain-top sites using standard vehicles or small trailers.
- Theater-Hardened Resilience: Constructed from anodized 6063T6 aluminum with 316 stainless steel fasteners, the antenna is immune to salt fog and high humidity. The epoxy-sealed connections ensure the structure survives decades in harsh coastal or industrial climates.
- Equipment Protection: The direct D.C. ground operation acts as a built-in lightning rod, providing a dedicated discharge path that safeguards expensive base station electronics from catastrophic electrical surges.
Primary Applications
1. Regional Repeater Backbone: The ideal solution for establishing the "master" repeater at a high-elevation site to provide wide-area voice and data coverage for police, fire, and emergency services.
2. High-Power Paging Networks: Ideally suited for regional paging systems that require high power handling (500W) and an omni-directional pattern to penetrate buildings and urban environments.
3. Multi-Channel Communication Hubs: Perfect for commercial radio sites where multiple carriers co-locate, providing a stable, low-noise platform for combined antenna systems.
4. Long-Haul Terrestrial Links: Used for spanning vast, sparsely populated areas or bridging communication between distant islands where satellite backhaul is not a viable option.
5. Tactical Field Command: The sectional design makes it a candidate for semi-permanent command centers in large-scale disaster recovery or military logistics hubs where a high-gain VHF backbone is required.
Design Features: The SD9-150 ultra high performance VHF band stacked dipole array is designed for use with highly populated radio sites requiring long haul omni-directional coverage. The SD9-150 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 gain and VSWR over its 15 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 eight dipoles. The SD9-150 High gain stacked dipole array operates at D.C. ground for protection against lightning.
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