Description

This portable HF antenna is a complete 6-80 meter OCF (off-center fed) vertical L dipole type HF antenna that is pre-tuned and requires no moving clips on coils or readjusting of whips for tuning. You should also use an external antenna tuner if your antenna is installed over a poor ground or not placed in a clear area.

When fully deployed with the NVIS, Vertical & Grounded Counterpoise elements, the balance of this OCF dipole type Alpha HF antenna system can be configured to launch your signal at your target in the opposite direction the NVIS element is run. For an omnidirectional signal pattern, you may remove the NVIS element.

Installation Note: Never Remove or Loosen any of the Bolts, Washers, Nuts, or Caps on the Match.

Included:

1 – 41×7.5×7.5 inch padded Expedition Bag that holds all of the following:
1 – 6 foot Heavy Duty (HD) aluminum tripod (for extended deployments)
1 – 13 feet 1 1/2 inch .433 OD MilStick vertical whip made from 26 inch section aluminum elements
1 – Alpha Match encased in a FMJ (Full Metal Jacket) 316 Stainless Steel and weather proof housing that shields all internal components from all RFI (Radio Frequency Interference).
1 – NVIS element wire.
1 – Grounded counterpoise wire with ground stake

Technical Data:
• Weight – Stowed Size: 212 ounces & 41 x 7.5 x 7.5 inches
• Antenna Type: OCF Standing L Dipole
• RF Connection: SO-239
• Max Power (Watts): 250 PEP SSB, 125 CW, or 25 watts for digital modes
• Impedance: 50 ohms
• Supported Bands: 6m, 10m, 12m, 15m, 17m, 20m, 30m, 40m, 60m, 80m

Analysis of the FMJ antenna when on the HD tripod

3D Model of the Alpha Antenna® HD-FMJ system

Gain and Elevation/Azimuth patterns with default configuration
Although the FMJ has directionality, it does not have more gain than a resonant vertical that in and of itself would have no more than -1.1 dBd of gain.

ANALYSIS WHEN USING OPTIONAL ELEMENTS

OPTIONAL FOUR 35′ NVIS ELEMENTS

* Analysis & Specifications for optional configuration using 4 (four) 35′ NVIS elements
Instructions – Deploy using 1 (one) 13′ Vertical Element, 1 (one) grounded counterpoise, and the optional 4 (four) NVIS Elements each at 90 degrees from the other in lieu of the single wire NVIS element.
HF Frequency Coverage – 1.6MHz to 30MHz when using a tuner if ground conditions are poor
Power – 250W PEP SSB, 125W CW, or 50W for sporadic use of digital modes (25W for continuous use of digital modes

* Gain and Elevation/Azimuth pattern using four 35′ NVIS elements
Omni-directional pattern using the four 35′ NVIS element installed directly under the portable HF antennas Vertical element on the top bolt of the Match on the tripod, with the Grounded Counterpoise installed on the bottom bolt of the Match.

OPTIONAL 60′ ELEMENT

* Analysis & Specifications for optional configuration using 1 (one) 60′ element
Instructions – Deploy using 1 (one) grounded counterpoise and the optional 1 (one) 60′ end-fed half-wave dipole element in lieu of both the 13′ vertical and the single wire NVIS elements.
HF Frequency Coverage – 3.5MHz to 30MHz without a tuner
Power – 250W PEP SSB, 125W CW, or 50W for sporadic use of digital modes (25W for continuous use of digital modes

Examples of Gain and Signal Pattern information for an end fed half wave dipole can be seen HERE

ADDITIONAL INFORMATION

Difference between FMJ and MIL 2.0

Other than the physical differences, the FMJ that uses a longer Mil-Stick and is more balanced with a Grounded Counterpoise resulting in better SWRs and stainless steel housing for higher RFI rejection than the MIL 2.0, which is more compact than the FMJ.

Advancements included with the HD-FMJ system that have been updated over other options:

No Guying: The HD Tripod wraps around and protects the antenna system when stored. This tripod has built in talons at the base of each leg that can be pressed into the ground with a built-in heel step at the base of each tripod leg. This enables the tripod to be used in most common environmental conditions without guy wires.

Touch free operations: The FMJ system enables you to switch bands or change frequencies without having to chance switches, jumpers, or coils.

Increased ERP (Effective Radiated Power): The electrically balanced OCF dipole circuit of the FMJ line of systems has an increased ERP over the base fed vertical (end-fed) antennas that use lossy matches to force low SWRs.

Directionality is a unique feature to the FMJ line of systems: The combination of a Vertical element with the NVIS and Grounded Counterpoise elements provide for a directional antenna system that enhances lower take off angles for increased DX communications, while simultaneously enhancing NVIS (Near Vertical Incident Skywave) for stateside communications.

The Alpha Match is a balanced 316 stainless steel housing: The Alpha Match is a transformer that is wrapped in a tar paper dielectric, which is then enclosed in a 316 stainless steel housing. This is what gives the Alpha Match both the capacitive and inductive balance. Once the elements are installed, then their capacitive characteristics enables RF to radiate. It is important to note that the Alpha Match housing is made of 316 stainless steel, which is non-magnetic and this helps to eliminate eddy currents.

Electrically conductive Industrial strength MilStick whip: The composite of the .433 inch diameter MilStick whip is a high strength, high quality, aerospace 7075-T9 alloy 13 feet long. The construction of each element has a scratch-resistant hard-anodized surface. This surface is fully removed from each insert and also removed 2.5 inches inside each element. The inserts are then electrically bonded, where full contact RF continuity and connectivity is used to ensure maximum efficiencies are achieved. At the base of the whip an embedded 8740 Steel (chrome moly) cadmium plated stud supports the MilStick on the Match.

Memory free industrial Wiring is used: Sheathed memory free wiring is used, which is rated for temperatures from -40°C to +175°C vs wiring that is so light duty that it can be wrapped around a kite string holder.

A Padded Field Bag: The various sized padded field bags for our portable HF antennas are made from 600D nylon, which includes an embroidered logo and high quality zippers. This highly customized bag also has a padded front pocket and a padded larger inner compartment, plus a shoulder strap with padded shoulder pad.

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