Issue link: https://te.mouser.com/i/1472770
AEROSPACE, DEFENSE & MARINE /// WHITE PAPER PAGE 2 AVIATION, NOISE AND THE CONNECTED PASSENGER Michael Coon, Field Application Engineer With renewed interest in how and when air travelers can use personal electronic devices (PEDs), EMI control deserves a new look. That commercial aircraft are handling more data for flight operations is well known. From navigation to fly by wire, electronics play an ever increasing role. Passenger connectivity is also growing. In-flight entertainment systems are more than movies—air travel is a matter of having your office in the sky. The use of PEDs pose a threat to critical flight electronics, both through radiated and conducted EMI. In-flight entertainment cabling can be thought of as laying an antenna through the cockpit. As with any antenna, the cabling can be both a source and receiver of emissions. IFE systems and PEDs must fall into the frequency spectrum from 2.4 GHz to 5 GHz, which is a "dead zone"—also called the Boeing notch—for flight electronics. Normal LAN wireless can operate safely without interference in these operating frequencies. The table below shows typical frequency ranges for flight electronics and PEDs. Laptops and tablets generally are not of concern since they do not share frequency bands with avionics. The only overlap is GPS. Portable satellite GPS tracking devices and smart phones with internal GPS tracking use the same frequency band as the aircraft's on-board GPS tracking and may conflict with the cockpit systems. The IFE architecture must not conduct or amplify RF frequencies above 5 GHz (which enters into the realm of GPS). As a consequence, handheld GPS devices are not approved for use in flight. Flight Electronics Frequency Range (MHz) VHF Omnidirectional Range (VOR) 108 - 118 Instrument Landing System Localizer (ILS LOC) 108 - 112 Instrument Landing System Glide Slope (ILS GS) 329 - 335 Distance Measuring Equipment (DME) Traffic Alert and Collision Avoidance System (TCAS) 960 - 1215 GPS L2 1227.5 GPS L2 1575.42 PEDs Cellular 824 - 849 Personal Communications System (PCS) 1850 - 1910 900-MHz ISM 902 - 928 2.4 GHz ISM 2400 - 2485 GPS L2 1227.5 GPS L2 1575.42