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Specifications 2D-40A


The 2D-40A is a 2-driven-element array for the 40-meter amateur band. It features full size elements, an internal phasing line, and an patented integral BALUN feed system. This beam has gain comparable to a 2-element Yagi, and a front-to-rear ratio comparable to a 3-element Yagi.

Physical Specifications

Wind Survival (no ice): 100MPH (85 Knots)


Elements: Aluminum, 6061-T6

Accessories: Aluminum, Steel, PVC, and Acrylic


Element Diameter: Elements taper from 2.50 inches to 0.375 inches

Element length: Front, 66.2 feet. Rear, 70.2 feet

Element sag: Front, 27.9 inches. Rear, 30.6 inches

Turn Radius: 36 feet

Weight: 163 pounds, including mounting plates and hardware

Projected area: 16.8 square feet

Electrical Specifications

Rated Power: 1.5KW CCS, 3KW ICAS

Feedpoint Impedance: Adjustable to exactly 50 Ohms

Operating Bandwidth

The VSWR bandwidth will be approximately as follows when measured at the antenna terminals. Measurements made at the transceiver end of the feedline may show wider bandwidths than these.

For 2.6:1 VSWR: 295 kHz (36% of the range is below F0 and 64% is above)

For 2.0:1 VSWR: 206 kHz (39% of the range is below F0 and 61% is above)

For 1.4:1 VSWR: 94 kHz (45% of the range is below F0 and 55% is above)

Minimum VSWR: Set to 1.0:1 at F0


Gain: 6.5-dBi minimum (free space)

11.9 dBi (approximately - NEC2 model) when array tuned for F0 = 7.1 MHz and mounted 70 ft (21 meters) above local earth.

Front to rear ratio: 20-dB minimum

Takeoff angle: 26.5 degrees

Vertical Beam width: 33 degrees -3dB 13 and 46 degrees. See patterns and associated notes.

Horizontal Beam width: 74 degrees

Download the 2D-40A Manual Adobe Acrobat file. (Manual updated 2003 Jun 24)

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