Grazioli Antenne HF Vertical Antennas and Packages

Grazioli Antennas MV7 HF/6M Multiband Vertical Ground Plane Antennas

The Grazioli Antennas MV7 is a base-fed 1/4-wave multiband vertical ground plane antenna designed to provide coverage of the 40, 20, 17, 15, 12, 10, and 6-meter amateur radio bands from a single antenna system. Standing 29.4 ft (8.97 m) tall, the MV7 expands upon the proven MV6 platform by adding 40-meter capability while maintaining a compact footprint and efficient multiband operation. 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 strength, durability, and long-term corrosion resistance. Rated for up to 1,500 watts SSB on 40 meters and 3 kW on all other bands, the MV7 is engineered for demanding amateur radio applications. Each antenna includes a detailed assembly manual and a unique serial number identifying the production batch and manufacturing data for quality traceability. Note: The MV7 includes a guying wheel for use with non-conductive guy ropes. Guying is recommended when the antenna is installed in areas subject to high wind conditions. Dual-Band 40/20 Meter Radiating System The MV7 is based on the established MV6 platform but incorporates a specially designed dual-band 40/20-meter central radiator. A loading coil combined with a capacitive top section allows the antenna to operate efficiently on both bands by isolating portions of the 20-meter radiator while providing the required inductive loading for 40-meter operation. The upper radiating section utilizes telescoping tubes that allow adjustment and calibration across the entire 40-meter band while presenting minimal wind resistance. DBFC Counterpoise System A key innovation of the MV7 is its DBFC (Dual Band Folded Counterpoise) system, a unique design developed to extend antenna performance to 40 meters without requiring long wire radials or loaded radial systems. The DBFC system uses a lightweight AISI 316 stainless steel stranded cable attached to one of the antenna's radials to create a dual-band electrical counterpoise. The combined length of the cable and aluminum radial forms an approximately quarter-wave counterweight on 40 meters while remaining compact through a folded arrangement. This design allows lower-frequency operation while preserving the performance characteristics of the higher amateur bands. FAIR-RITE RF Choke System The MV7 is supplied with an original FAIR-RITE FT240-43 ferrite toroid manufactured in the USA for construction of a high-performance RF choke. When installed directly below the antenna feed point, the completed choke significantly attenuates common-mode currents throughout the HF spectrum from 1.8 to 30 MHz, helping to improve antenna efficiency and reduce unwanted RF on the feed line. Proprietary High-Power UHF Connector Rather than utilizing a conventional commercial SO-239 connector, the MV7 employs a proprietary connector engineered and manufactured by Grazioli. The connector features a true 50-ohm characteristic impedance and is rated for operation up to 500 MHz. Its robust design supports 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 reliable electrical contact. A PTFE insulator provides excellent electrical and thermal performance, and a protective elastomer hood helps prevent water and moisture intrusion. Heavy-Duty Mounting System The mounting bracket is fabricated from 0.098 in (2.5 mm) thick AISI 304 stainless steel and secures to the antenna using a robust clamping system designed for long-term mechanical stability. Mast attachment is accomplished through an AISI 304 stainless steel M6 V-bolt and column-nut assembly, providing secure installation and dependable support in demanding outdoor environments.

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