DMN4-26 Antenna, C Female Connector, 108 to 112 MHz, 50 Ohm, Forward Looking Lobe, <5:1

Overview

The N4-26 is an airborne, localizer antenna for bulkhead installation, navigation antenna. The N4-26 Antenna has been designed specifically to provide optimal pattern coverage for reception of localizer signals and is standard equipment on all models of the Boeing 737. When installed on the forward bulkhead, where forward-looking pattern coverage is unimpeded, the N4-26 will provide significantly better performance (for localizer functions) than any tail-mounted very high frequency omnidirectional radio range localizer (VOR/LOC) antenna. This installation technique greatly extends the service life of the antenna because it is protected by the aircraft’s radome. The center-fed loop design of the N4-26 outperforms most dipole-based localizer antennas by providing significantly better resistance to cross-polarized signals (thus improving instrument landing system accuracy) and a broad, amplitude-stable pattern lobe. The center-fed loop design also eliminates any sensitivity to the motion of the weather radar assembly. An integrated coupler provides isolated, redundant, radio frequency outputs allowing use of one antenna with two navigation receivers. L3Harris recommends the N4-26 for installation on aircraft where tail-mounted VOR/LOC antennas may not provide satisfactory localizer performance. In general, a tail-mounted VOR antenna will be used in conjunction with the N4-26 to provide optimal VOR signal reception.