EMC failures show how electromagnetic interference can escalate far beyond its source—from hospital HVAC shutting down MRI scanners to disruptions at Obama's inauguration and hospital shutdowns. These engineering problems demonstrate that EMC issues can strike anywhere with unpredictable, wide-reaching consequences.
In 2013, a test equipment product was failing EMI compliance by 10-12 dB. The engineer discovered power modules were shorting signal ground to chassis at two points 16 inches apart, turning the chassis into a radiating antenna. Disconnecting these shorts immediately dropped emissions from 12dB to 4dB above the limit.
Source: https://www.edn.com/tracking-a-moving-target/
During a hospital renovation, HVAC variable frequency drives caused false MRI readings through conducted emissions traveling via the building's electrical system to the sensitive medical equipment. The quickest fix was installing a separate electrical service for the MRI machines.
Source: https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=6512209
Since 2004, U.S. Defense radios reportedly impaired tens of thousands of garage door openers. The garage door openers lost their ability to function when the military systems transmitted. This became a political issue as angry homeowners complained about their non-functioning garage doors.
Source: https://spectrum.ieee.org/peaceful-coexistence-on-the-radio-spectrum
Smart grid deployments in Sweden created widespread EMC problems. Kilowatt-hour meters sending data through power lines interfered with dimmer lamps and electrical appliances. Household electronics interfered back with the smart meters, causing registration errors. Wind power plant electronics also disrupted meter readings sent as power line signals.
Source: https://incompliancemag.com/DigEd/inc1303/offline/download.pdf
During a 1985 Spacelab mission, crew used a middeck vacuum cleaner instead of the lab's designated vacuum. Switching it on caused voltage drop and shut off the Remote Acquisition Unit. The vacuum hadn't been EMI tested for lab use, showing the critical importance of EMC testing even in space.
Source: https://ntrs.nasa.gov/citations/19960009442
In 2007, a consultant found circuit design flaws still appearing in new designs despite being solved decades ago. Ground plane breaks cause signal paths to cross gaps, creating large loops that increase EMI emissions and ESD susceptibility. When breaks were filled on one board, emissions reduced and analog performance improved.
Source: https://www.emcesd.com/tt2007/tt060207.htm
In 2011, a regional airliner climbing past 9,000 feet had its compasses go haywire, leading pilots several miles off course. A flight attendant convinced a passenger in row 9 to turn off their iPhone, and the heading problem was immediately solved. The plane landed safely, and the FAA has logged dozens of suspected interference cases from passenger electronics since 2002.
In 2013, microwave signal interference disrupted one of 12 giant video screens during President Obama's inauguration ceremony. Officials couldn't determine the interference source, and crews in the same area couldn't communicate on walkie-talkies while the screen was experiencing problems. A dedicated channel for the inauguration feed showed no equipment failure.
An important Goldman Sachs meeting had trouble getting year end figures due to teleconference noise from board members' electronic devices. The devices were continuously polling and converting RF signals to audio noise. This incident led to development of an ANSI standard for office equipment RF immunity.
Source: https://www.electronicdesign.com/home/article/21201153/an-update-on-the-c63-standards
A person wrote to New Scientist about effects from a piezoelectric lighter spark device. Creating a spark between the device and a radiator caused room lights to flicker and made their computer think all USB devices were unplugged. The question sought explanation for these simultaneous disruptions.
Source: https://www.newscientist.com/lastword/mg22029471-900-bright-spark/