DM N4-4

The DM N4-4 Antenna System has been designed to minimize bearing errors in the reception of VOR and ILS signals. It provides considerably more gain at the horizon (particularly during banks) than do fuselage mounted "deerhorn" or "vee" antennas. It has substantially greater discrimination against vertically polarized signals; and when properly installed on helicopters it provides much greater rejection of rotor modulation than can be obtained with these other antennas. As a result, it provides better signal to noise ratios and smaller errors than is otherwise available.
The DM N4-4 Antenna consists of two (approximately semicircular) center-fed half-loops and cable harness. Because the DM N4-4 has been designed specifically for light planes and helicopters, lightweight rugged construction has been stressed. It is built of round magnesium tubing and weigs only 2 pounds.

Electrical
Frequenc y Range	108 - 122 MHz
VSWR	Less than 5.0 to 1
Polarization	Horizontal
Radiation Pattern	Omnidirectional in the azimuth plane. Approx cos. 0 in the vertical plane.
Gain	0 +/- 2 dB
Impedance	50 Ohms
Efficiency	95%
Mechanical
Weight (without cable)	2 lbs
Military	MIL-E-5400 MIL-T-5422
FAA	TSO-C40a
Connectors	BNC

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