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MV3 by Grazioli antennas is a vertical HF tri-band 1/4 λ Ground Plane which operates on the following bands: 20, 15, 10 metres.
It is an entry-level antenna, lightweight and robust, which does not require any bracing, and is the solution best suited for performance, lightness (just 5 kg) and is suitable for those installations that require a low visual impact.
It has 4 radial earthing wires, each measuring 2.4 m in length + one radial in a single run (previously used on the MV7) in cord made of 316 stainless steel, which ensures perfect operation of all the strips even for installations located in all bands even for installations located near the ground or on the roof.
This device known as DBFC an acronym for “Dual Band Folded Counterpoise” makes this system unique in its kind and avoids the use of radial loaded cables which would cause losses, or the installation of radial strings to be arranged on the roof which might be difficult to install and secure.
MV3 is a “RESONANT” antenna and therefore powered directly without the use of adapters or transformers for impedance which would introduce losses and would would limit the power that can be applied, is equipped with inductance at high impedance which causes a short circuit in DC, discharging to earth any interference caused by events in the atmosphere and/or discharges electrostatic.
The antenna is made from tubes of medium cross-section and thickness, whilst the components made of aluminium are machined from solid stock using CNC machines, the cross-pieces which spacer the stubs are made of thermoplastic material moulded by injection moulding and protected against UV rays, and is supplied with an FT240-43 toroid from FAIR-RITE USA, for the construction of an efficient choke to be installed immediately below the connector.
UHF connector
The antenna connector is not the commercial SO-239 type used by most manufacturers. Our connector is designed and built directly by ourselves; it has a true 50 Ohm characteristic impedance and is rated up to 500 MHz. We have created a reliable connector capable of withstanding 5 kW of continuous RF power at 30 MHz and greater than 3 kW at 50 MHz.
The body is made of CW614N nickel-plated brass, while the pin is plated in 24K gold to avoid oxidation and is equipped with a 4-fin insulator that maintains its centring and elasticity to avoiding contact losses.
The insulating material is PTFE, one of the best insulators due to its exceptional electrical and thermal properties (low dielectric constant and reduced loss factor, operating temperature from -100 to +260 °C). The assembly is protected by a special elastomer hood that prevents water and humidity infiltration.
