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The Hy-Gain Model 5BDQ-S is a versatile multi-band doublet antenna designed for amateur radio enthusiasts. It operates across five popular bands: 10, 15, 20, 40, and 80 meters, offering broad coverage for various communication needs. The antenna's design incorporates matched Hy-Gain Hy-Q traps, which are key to its automatic band switching capability, simplifying operation for the user. This means the antenna automatically adjusts to the selected band without manual intervention, providing a seamless experience for multi-band operation.
A notable feature of the 5BDQ-S is its fanned wire configuration. The 15-20 meter wire is positioned below the 10-40-80 meter wire, a design choice specifically implemented to minimize loading. This careful arrangement contributes to the antenna's efficient performance across its operational bands. The antenna has a maximum overall length of 93 feet 8 inches, which is a significant dimension that should be considered during installation.
For enhanced performance, the manual recommends using the Hy-Gain balun Model BN-86. This broadband balun is specifically designed for doublet-type antennas like the 5BDQ-S. Its primary function is to balance the input impedance to the antenna, ensuring optimal power transfer from the transceiver. Additionally, the BN-86 balun helps prevent transmission line radiation, which is crucial for increasing the overall efficiency of the doublet antenna and minimizing interference.
The construction of the 5BDQ-S emphasizes durability and longevity, particularly for outdoor use. The Hy-Q traps, which are integral to the antenna's functionality, are designed to be weather resistant, ensuring reliable operation in various environmental conditions. All hardware components used in the antenna's construction are made from stainless steel, a material known for its excellent resistance to corrosion and rust, further contributing to the antenna's lifespan.
The center of the doublet is supported by a robust yoke-type center insulator. This insulator not only provides structural support but also serves as the attachment point for the transmission line. The ends of the doublet are supported by end insulators, which are constructed from high-impact Cycolac® plastic. This material is chosen for its strength and durability, capable of withstanding environmental stresses. The antenna wire itself is made from Alumoweld® #212, a high-strength material with a breaking strength of 1200 pounds. Alumoweld is also resistant to rust and corrosion, making it an ideal choice for long-term outdoor deployment. The manual includes "Hints on Handling Alumoweld Wire," indicating that while durable, it may require specific handling techniques due to its properties.
The Model 5BDQ-S antenna is designed for use with a single 50-ohm coaxial feedline, a common standard in amateur radio. It is engineered to achieve a Standing Wave Ratio (SWR) at resonance of 1.5:1 or less on all bands, indicating efficient power transfer and minimal reflected power. For the feedline, either RG-58/U or RG-8/U coaxial cable can be used. The manual specifically recommends RG-8/U polyfoam type cable due to its lower losses and higher power handling capabilities, which can be beneficial for maintaining signal integrity, especially over longer cable runs or with higher power transmissions.
Installation of the 5BDQ-S requires careful attention to detail to ensure optimal performance. The end insulators should be attached to a stable structure, while the center insulator can be supported by the antenna itself or from an external support. If supported externally, it's critical that the insulator does not contact the supporting structure. For proper operation, the center insulator should be at least 46 feet above the ground, with the general rule being that a higher antenna typically yields better performance.
The antenna should be mounted in a clear area, free from obstructions. The manual highlights that surrounding objects, especially power lines and other metal structures of significant length or mass, can detrimentally affect antenna performance. Therefore, careful site selection is essential. When installing, it's important to keep the two halves of the antenna balanced with respect to ground and surrounding objects. Any imbalance can lead to serious deterioration in performance. The manual also advises against attempting to remove all sag from the antenna wires, as this can create tremendous strain and lead to mechanical failure. A few feet of sag in the center is considered normal and will not harm the antenna electrically or mechanically.
When suspending the antenna, the 10-40-80 meter wire should be kept as horizontal as possible, and the 15-20 meter wire should be fanned below it. Specific separation distances, as illustrated in Figure 1 of the manual, must be observed. The lower ends of the antenna must be at least 16 feet above the ground. The principle of balance extends to the ends of the antenna: any modification made to one end must be mirrored on the other to prevent performance degradation. The antenna package includes 100 feet of rope for suspending the end insulators. The end insulators feature two different sized holes; the larger one is for attaching the rope. If additional suspending material is needed, non-metallic rope is recommended. If wire must be used, it should be broken up every 6 feet with strain insulators to prevent harmful effects on the radiation pattern.
The step-by-step assembly instructions guide the user through the process, starting with the center insulator. The process involves stripping coaxial cable, soldering conductors to solder lugs, and securing components with bolts and nuts. Silicone grease or Vaseline® (not supplied) is recommended for mating insulator halves to ensure a weather-tight seal. The manual emphasizes that both sides of the antenna are identical, and each step should be performed for one side and then repeated for the other.
Wire cutting dimensions for the 10-meter wire (L1) are provided for both Phone and Continuous Wave (CW) operations, with an additional 3 inches on each end for attachment. The manual stresses that once a mode of transmission (Phone or CW) is selected, it must be consistently used for all dimensions. Wires are attached to insulators and traps using wire locks, and any excess wire extending past the lock should be clipped off. A critical detail is that the end of the trap marked with the part number must always point toward the center insulator, as this is essential for proper antenna operation. Similar instructions are provided for cutting and attaching the 40-meter antenna wire (L2) and the 80-meter antenna wire (L3), ensuring correct trap orientation and wire attachment.
The manual also provides guidance on removing kinks from Alumoweld® wire, which can be more difficult to work with compared to other wire types due to its strength. Kinks can be removed using a pole or similar stationary curved object by working the wire back and forth. This attention to detail in handling the wire underscores the material's unique properties and the importance of proper technique for successful assembly. The comprehensive instructions aim to ensure that even users unfamiliar with antenna assembly can successfully set up their 5BDQ-S for optimal performance.
General| Element Material | Aluminum |
|---|---|
| VSWR | 1.5:1 |
| Impedance | 50 Ohms |
| Elements | 5 |
| Polarization | Horizontal |
