Grazioli Antenne HF Vertical Antennas and Packages

Grazioli Antennas MV6 HF/6M Multiband Vertical Ground Plane Antennas

The Grazioli Antennas MV6 is a high-performance, base-fed 1/4-wave multiband vertical ground plane antenna designed to provide coverage of the amateur 20, 17, 15, 12, 10, and 6-meter bands from a single compact installation. With an overall height of 22.1 ft (6.75 m) and a continuous power handling capability of up to 3 kW in all operating modes, the MV6 delivers full-size antenna performance while maintaining a practical footprint for demanding HF and VHF installations. The antenna features heavy-duty construction utilizing premium AW6063-T66 aluminum alloy tubing, precision CNC-machined components, and high-quality AISI 304 and AISI 316 stainless steel hardware for exceptional mechanical strength, durability, and long-term corrosion resistance. Each antenna includes a detailed assembly manual and a unique serial number for complete production traceability. Multiband Radiating System The MV6 employs an innovative multiband design consisting of a central radiator dedicated to the 20-meter band and four resonant radial elements that provide operation on the 17, 15, 12, 10, and 6-meter amateur bands. Unlike trapped multiband designs, the radial elements are true quarter-wave resonators and do not utilize traps that can introduce additional losses and reduce efficiency. The antenna is fed directly without impedance transformers or matching devices that could limit power handling or negatively affect overall efficiency. A high-impedance inductance incorporated into the feed system creates a DC-grounded path that helps dissipate electrostatic charges and atmospheric disturbances. Band tuning is accomplished through adjustment of the telescoping sections of the central radiator and radial elements, allowing each operating band to be independently calibrated. The only interaction occurs between the 17-meter and 6-meter sections, where adjustment of the 17-meter resonator also influences 6-meter resonance. Grazioli recommends the use of a graphical antenna analyzer such as RigExpert or NanoVNA to simplify the tuning process. Common-Mode Current Suppression The MV6 is supplied with an original FAIR-RITE FT240-43 ferrite toroid manufactured in the USA for the construction of a high-performance RF choke. When properly assembled, the choke significantly attenuates common-mode currents across the HF spectrum from 1.8 to 30 MHz, helping to improve antenna performance and reduce unwanted RF current on the feed line. Grazioli recommends installing the completed choke directly below the antenna feed point to minimize the possibility of RF feedback on the coaxial cable. Proprietary High-Power UHF Connector The MV6 utilizes a proprietary connector designed and manufactured by Grazioli rather than a conventional commercial SO-239. The connector features a true 50-ohm characteristic impedance, is rated for operation up to 500 MHz, and can handle 5 kW continuous RF power at 30 MHz and more than 3 kW at 50 MHz. The connector body is manufactured from nickel-plated CW614N brass, while the center pin is 24K gold-plated to prevent oxidation and maintain excellent electrical contact. A PTFE insulator provides outstanding electrical and thermal performance over an operating temperature range of-148°F to 500°F (-100°C to +260°C), and the assembly is protected by a dedicated elastomer weather hood to prevent moisture intrusion. Heavy-Duty Mounting System The MV6 mounting bracket is fabricated from 0.098 in. (2.5 mm) thick AISI 304 stainless steel and attaches to the antenna through a clamping system that creates an extremely robust mechanical connection. Mast attachment is accomplished using an AISI 304 stainless steel M6 V-bolt and column nuts, providing secure installation and reliable long-term support in demanding operating environments.

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