VOR/LOC BAL LOOP "TOWEL BAR" (DM N4-4) 
Frequency Range 108-122 MHz 

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.

Specifications

• Frequency 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%
• Weight: (without cable) 2 lbs
• Military: MIL-E-5400
• MIL-T-5422
• FAA: TSO-C40a
• Connectors: BNC