Grazioli HW20V

Grazioli HW20V – 20m HF Vertical Antenna

Main Features

• ½ λ vertical antenna, base-fed for the 20m band, finely tuned using a PTFE-insulated high-voltage variable capacitor.

• Extremely robust construction using AW6063-T66 aluminium alloy and CNC-machined solid components.

• Supplied with high-quality AISI 304 and 316 stainless steel hardware for long-lasting, corrosion-resistant operation.

• High power handling capability: up to 3 kW continuous, all modes.

• Includes a detailed assembly manual and a unique serial number identifying the production batch and construction specifications.

• Supplied with a three-point guying clamp. We strongly recommend using guy ropes for additional stability.

Materials and Construction

For the antenna tubing, we use one of the finest aluminium alloys available for antenna construction: AW6063-T66.
This aluminium alloy, consisting of aluminium, magnesium and silicon, is heat-treated to a T66 temper, providing exceptional mechanical strength and resistance.
The tubes are manufactured through extrusion followed by cold drawing. They feature extremely precise outer and inner diameters, as well as consistent wall thickness, ensuring an accurate fit and minimal play between the sections.

Electrical Specifications

Mechanical Specifications

High-Q LC Matching Circuit
For this antenna, we have developed a special parallel LC matching circuit to adapt the high impedance presented by this type of base-fed antenna.

The generously sized high-Q coil is air-wound, with widely spaced turns and no metallic core. The coaxial variable capacitor, similar to a Gamma Match, is positioned at the base of the antenna next to the coil, allowing easy and precise tuning.

The capacitor features PTFE insulation and can withstand extremely high voltages exceeding 40 kV. It is virtually unaffected by ambient temperature, rain or humidity and does not overheat under high-power operation.

During the development of the matching circuit, both inductance (L) and capacitance (C) were carefully adjusted to achieve a highly efficient, reliable and trouble-free system.

The result is excellent efficiency combined with the ability to handle RF power levels of up to 3 kW continuous, all modes.

Additionally, the coil is directly DC grounded, significantly reducing atmospheric noise.

High-Quality UHF Connector
Unlike the standard SO-239 connectors commonly used by other manufacturers, our antenna features a specially designed connector, developed and manufactured in-house.

It has a true 50-ohm characteristic impedance and is rated for frequencies up to 500 MHz. This high-quality connector is designed to withstand up to 5 kW of continuous RF power at 30 MHz and more than 3 kW at 50 MHz.

The connector body is manufactured from CW614N nickel-plated brass, while the centre pin features 24K gold plating to prevent oxidation.

A four-fin insulator ensures perfect centring and maintains the necessary elasticity to prevent contact losses.

The insulating material is PTFE, one of the finest electrical insulators available, thanks to its excellent electrical and thermal properties. It offers a low dielectric constant, minimal loss factor and an operating temperature range from -100°C to +260°C.

The entire assembly is protected by a special elastomer sealing boot, preventing water and moisture from entering the connection.

Heavy-Duty Mounting Bracket
The mounting bracket is manufactured from 2.5 mm thick AISI 304 stainless steel.
It attaches to the antenna tube using a clamping system, creating an exceptionally strong and secure mechanical connection.
The mast mounting assembly consists of an AISI 304 stainless steel M6 V-bolt and column nuts, allowing easy and secure tightening.

Frequently Asked Questions

Which amateur radio band is the HW20V antenna designed for?
The Grazioli HW20V is a ½ λ HF vertical antenna, base-fed and specifically designed for the 20-metre amateur radio band (14 MHz), offering full-band coverage.

What is the total height and weight of the HW20V?
The total height is 10.7 metres, and the net antenna weight is 5.4 kg.

What is the maximum power handling capability?
The HW20V can handle up to 3 kW of continuous RF power in all operating modes.

Which materials are used in its construction?
The antenna features high-quality AW6063-T66 aluminium alloy tubing, combined with fibreglass, brass and PTFE components. All hardware is made from AISI 304 and 316 stainless steel.

What is the antenna’s gain and radiation pattern?
The declared gain is 0 dBd (2.15 dBi), with an omnidirectional radiation pattern and vertical polarisation.

What are the wind resistance specifications?
The antenna has a wind surface area of approximately 0.265 m² and a wind load of 25 kgf at 130 km/h (without ice). It can withstand wind speeds of up to 130 km/h when properly secured with guy ropes.

What type of matching system does the HW20V use?
The antenna features a high-Q parallel LC matching circuit with DC grounding. It is equipped with a 50 Ω female UHF connector featuring a PTFE insulator and gold-plated centre pin.

What applications is the HW20V suitable for?
The Grazioli HW20V is ideal for amateur radio operators who primarily operate on the 20-metre band and require a high-performance, high-power vertical antenna. It is suitable for both rooftop and ground installations.