Grazioli MV6 vertical multiband HF antenna 1/4λ 3kW new version TOROID

Technical specifications :

• Frequency range: HF 20, 17, 15, 12, 10 + VHF 6m
• Type: 1/4 λ vertical dipole with end feed
• Impedance: unbalanced 50Ω
• Radiation: omnidirectional
• Polarisation: vertical - linear
• Gain : 0 dBd - 2.15 dBi
• Resonant SWR: ≤1.5:1
• Maximum applicable power: 3000 Watts continuous all emission modes
• Power system: direct - connected to DC earth
• Connector: UHF female (SO-239) with PTFE insulation, gold-plated centre pin

High-grade material : AW6063-T66 alloy of aluminium, magnesium and silicon hardened to T-66, ensuring maximum strength. Tubes are extremely accurate across both diameters and wall thickness, allowing precise coupling with no 'play' between tubes.

Specifications:

• Materials: AW6063-T66 aluminium tube, fibreglass, brass, PTFE, stainless steel screws
• Wind surface area: 0.4^m2
• Wind load at 130Km/h: 19 Kgf
• Wind resistance: 130 Km/h
• Total height: 6.75m
• Whip length: 6.20m
• Radial length: 2.7m
• Mast mounting: ø 40-54 mm
• Net weight: 7.8 kg

Warning: Installing this product near high-voltage lines is dangerous. Follow the instructions for your safety.

* Construction of the choke balun

The MV6 antenna is now supplied with a "Fair Rite" toroid made in the USA to create a choke balun to be installed under the antenna and to improve its performance.

The choke balun for the HF band (1.8-30 MHz), to be installed near the antenna connector, significantly attenuates sheath currents, which can reduce the antenna's performance and may cause interference in the station or high VSWR.

Grazioli Antenne supplies the original FAIR-RITE ferrite toroid (FT240-43 Made in USA) to create your own high-performance choke balun.

Material not supplied to be added by the customer for manufacture:

- 2 PL259 connectors adapted to the type of cable you are using. (1 PL259 + 1 SO239 if a plastic protection box is used)
- Approximately 1.2 m of good quality coaxial cable, type RG58 for continuous power up to 300 Watts at 30 MHz or RG142BU in Teflon for continuous power up to 1500 Watt AWG at 30 MHz.

Grazioli strongly advises against the use of cables with expanded FOAM dielectric (white spongy dielectric) as they cannot be wrapped around the toroid without compromising its electrical characteristics.

Instructions for building the choke balun

Take the coaxial cable, spread it out on a surface and mark half its length with a piece of insulating tape or a marker.

Then insert it into the toroid Fig.1 up to the mark, and secure it with a plastic clip, start winding the coils by passing the cable through the toroid at least 5 or 6 times, then do the 5 or 6 turns on the opposite side with the same procedure, until you get the balun like the one in Fig.2.

Secure the end of the winding with another clamp and your balun is complete. All you need to do now is install the connectors on both sides, and connect one side to the antenna and the other to the coaxial downlink.

If you want to attach it to the support mast, we recommend placing at least 4 - 5cm of wood or plastic between them to prevent them being affected by the metal mass.

To protect the balun, you can use a plastic enclosure for electrical installations, fitting an SO239 on the lower part of the enclosure towards the downlink, and a cable gland on the upper side, where the cable that will connect the outgoing aerial is located. Drill one or two holes in the base to drain off any condensation.