Grazioli FE6V 50-54Mhz 5/8

Main Features

Vertical 5/8 λ VHF antenna. Adjustable from 50 to 54 MHz with whip length adjustment chart.

Extremely robust construction in AW6063-T66 aluminium alloy.

Supplied with high-quality 304 and 316 stainless steel fasteners for long rust-free operating life.

The Ground plane consists of four full quarter-wave radials.

High input power, up to 2 kW continuous all-mode.

Detailed assembly manual and serial number that identifies the production batch and construction data.

MATERIALS AND CONSTRUCTION

For our tubes, we have used the best antenna construction alloy available: AW6063-T66 is an alloy of Aluminium, Magnesium and Silicon that is hardened to a T-66 temper which gives the stylus exceptional resistance. It is shaped by extrusion and subsequent cold drawing. Our tubes are extremely accurate on both diameters and also on the wall thickness, ensuring a precise fit with less ‘play’ between the tubes.

The "Ground Plane" is composed of four robust full-quarter wave radials with a length of 1,4 m. Each radial is a single-section tube with a diameter of 13 mm and wall thickness of 1,25 mm, fixed to the support plate by means of two U-bolts and self-locking nuts, in the fixing area. Four glass fibre reinforcements are provided to strengthen the joints and prevent the pipes from being crushed.

Electrical Data

Antenna Type:5/8 λ GP with 4 full ¼ d’wave radials

Frequency Range: Tunable from 50 to 54 MHz (with Graph)

Impedance: 50Ω Unbalanced

Radiation Type: Omnidirectional

Polarization: Linear – Vertical

Gain: 1,5dBd – 3.65dBi

Bandwidth @SWR 2:1: ≥ 3.1MHz @ 50MHz

SWR @resonance: ≤1.2:1 @ antenna connector

Max. Input Power: 2000 Watts continuos all mode

Feed system: high-Q air wound matching coil, DC-Ground

Input connector: 50Ω UHF female PTFE insulator, gold plated pin

Mechanical Data

Materials: Aluminnum Alloy AW6063-T66 hard drawn tube, Fiberglass, Brass, PTFE. All hardware are made of SS AISI-304 and 316

Wind surface area: 0,16m2

Wind load @ 130Km/h: 280N – 15,6Kgf 

Wind survival (no ice): 150 Km/h

Antenna Height: 4.17m a 50MHz

Radials length: 1,4m (Full quarter wave)

Mounting mast bracket: ø 40-54 mm

Antenna Net weight: 3.34 Kg

Package dimensions: 14x14x145 cm

Weight in package: 4,6Kg

Why build an antenna capable of withstanding 2kW of continuous power?

Because an antenna that accepts high power is a more efficient antenna. Otherwise, it would tend to heat up due to the Joule effect and dissipate a significant part of the applied RF power as heat, something that happens with most competing products but which, unfortunately, users cannot test for want of adequate equipment and instrumentation.

The high “Q” Coil

The coil plays a fundamental role for impedance matching and maximum RF transfer, its shape given by the length / diameter ratio, the pitch between turns, the material and diameter of the wire and the presence or absence of metal cores within it, determine the quality factor “Q”.

In simple terms, the higher is the “Q” value of the coil, the lower is the losses at high frequency.

We have created a generously sized coil suspended in the air without metal cores, with an L / D ratio of 1.3 and widely spaced turns, obtaining a “Q” value of about 2500 at a frequency of 28MHz, when the best competing antennas do not reach 1500.

This translates into maximum efficiency, and the ability to withstand high RF powers.

In addition, the coil is directly connected to ground in direct current (DC-Ground), in this way atmospheric disturbances and background noises are significantly reduced.

UHF Connector

The FE10V connector is not a commercial SO-239 type connector as most manufacturers use. The connector was designed and built directly by us, has a real impedance of 50 Ohms and can be used up to 500 MHz. The goal was to create a reliable connector capable of withstanding 5kW CW continuous at 30 MHz.

The body is made of CW614N nickel-plated brass, while the pin is plated in 24K gold to avoid oxidation and equipped with a 4-fin insulator that maintains its centering and elasticity, avoiding contact losses.

The insulating part is made of PTFE which is one of the best insulating materials due to its exceptional electrical (low dielectric constant, and reduced loss factor) and thermal (operating temperature from -100 ° to + 260 °) and is protected from a special elastomer hood that prevents water and humidity infiltration

The fixing bracket

Made of 2.5mm thick AISI304 stainless steel, it is fixed to the antenna tube by means of a clamp closure system, creating an extremely strong mechanical locking.

Fixing to the mast is made with AISI304 M6 V-Bolt and high type nuts to facilitate tightening.