Grazioli G-Max High Gain 27-28.5Mhz

Main Features

G-Max is the first and only vertical antenna in the world for the bands of 10 or 11m in a collinear configuration 5/8λ over 1/4λ with high gain.

Built on the mechanics of the well-proven FE10V this antenna has exceptional performance comparable or better than a 2 elements Yagi, but with the advantage that G-Max is omnidirectional.

G-Max does not fear comparison with any other vertical antenna on the market, whether they are 5/8 type, J-Pole, or other types on the market.

Thanks to its high gain, compressed main lobe with low radiation angle, it will guarantee you performance never seen before.

MATERIALS AND CONSTRUCTION

For our tubes we have used the best material that can be used for the construction of antennas; it is the alloy of Aluminum, Magnesium and Silicon called AW6063-T66, hardened to the state T-66. It gives the stylus an exceptional resistance, which is achieved by extrusion and then by cold-drawn.

Our tubular elements are extremely precise on both diameters, and also on the wall thickness, allowing a precise coupling with the least "play" between the tubes.

The "Ground Plane" is composed of 4 strong radials with a length of 2,7m, "Full-Quarter Wave" made in two telescopic sections with clamp fixing, with diameter and thickness respectively 13×1.25mm and 10x1mm.

The radials are fastened to the support plate by means of two U-bolts and self-locking nuts; in the fastening area there are 4 fiberglass reinforcements that strengthen the joints and prevent crushing.

Electrical Data

Antenna Type:Ground Plane Collinear 5/8λ over 1/4λ in phase

Frequency Range: Tunable from 27 to 28.5 MHz 

Impedance: 50Ω Unbalanced

Radiation Type: Omnidirectional

Polarization: Linear – Vertical

Gain: 3.5 dBd – 5,65 dBi

Bandwidth @SWR 2:1: ≥ 1,3 MHz a 27 MHz

SWR @resonance: ≤1.2 Typical ≤1.1

Max. Input Power: 5000 Watts continuos all mode

Feed system: Direct, with DC-Ground choke

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: 0,34m2

Wind load @ 130Km/h: 32.5Kgf 

Wind survival (no ice): 130 Km/h

Antenna Height: 10,85m a 27MHz 

Radials length: 2,7m (full quarter wave)

Mounting mast bracket: ø 40-54 mm

Antenna Net weight: 6.8 Kg

Package dimensions: 14x14x145 cm

Weight in package: 8,2Kg

The world's only Collinear Ground Plane for 10 or 11m

Grazioli "G-Max" is a vertical antenna type Ground Plane Collinear high gain, the radiator is made of two distinct sections fed in phase through a special aluminum coil properly positioned on the whip.

The feed is direct and takes place in the lower part of the whip that has a length of about 1/4λ, then through the phasing correction coil the RF signal goes to feed in phase also the upper part of length about 5/8λ.

The result is that the whole stylus of about 10.3m radiates in phase with a gain of almost 6dBi and a very low radiation angle (typical about 8°).

The Ground Plane is resonant with radial "Full Quarter Wave" that further enhance the performance, and reduce the radiation angle.

Made on the mechanics of the well-proven FE10V this antenna has exceptional performance comparable or better than a 2 element Yagi, but with the advantage that G-Max is omnidirectional.

NOTE: G-Max is supplied with 3 attacks guy clamp that we always recommend to put.

The phasing correction coil

The G-Max coil has been carefully placed at the ends of the two central radiating sections.

It performs three functions of extreme importance for this type of collinear antennas, the first has the task of delaying by 180° the phase of the RF signal between the first section at 1/4 Lambda and the second section at 5/8 Lambda, so that the whole radiating part (whip) radiates in phase.

The second function is to compensate for the strong capacitive reactance present on the top 5/8 section thanks to its intrinsic inductive reactance, and the third function is to transfer all the power fed to the top section without losses.

All this is made possible thanks to the high "Q" factor of our coil, designed to perform all three functions mentioned in the best possible way

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.