| Seems like this is a relatively common bug. Some months ago, in the HN thread for a blog post by the Lunar app developer and weird bugs people sent him, a commenters posts how this is a known bug and, for example, it's in DisplayLink's support database, and they even suggest some fixes: "Surprisingly, we have also seen this issue connected to gas lift office chairs. When people stand or sit on gas lift chairs, they can generate an EMI spike which is picked up on the video cables, causing a loss of sync. If you have users complaining about displays randomly flickering it could actually be connected to people sitting on gas lift chairs. Again swapping video cables, especially for ones with magnetic ferrite ring on the cable, can eliminate this problem. There is even a white paper about this issue." HN Thread: https://news.ycombinator.com/item?id=32631017 DisplayLink support: https://support.displaylink.com/knowledgebase/articles/73861... Lunar app bugs: https://notes.alinpanaitiu.com/Weird%20monitor%20bugs Edit: Looking around I've found this funny/interesting short paper from 1999 called "Unusual Forms of ESD and Their Effects". They refer to a Japanese paper already in 1993 pointing to chairs ESD disruption, and also to using a ziplock bag with a bunch of coins to test ESD protection... Short and interesting! : https://www.emcesd.com/pdf/uesd99-w.pdf Edit 2: Interesting 2006 research about one of the researchers for the 93 paper: "ESD noise radiated from walkers was observed in the 5-GHz-band to study the influence on the quality degradation of radio communication. We determined that the radiated ESD noise in the 5-Gk-band is originated by "Collision ESD" and "Induced ESD" when people walk while wearing metal objects." https://ieeexplore.ieee.org/document/5256785 |
I would like to do EM scans around my house just out of curiosity, and the graph is nice.
Is this an application for a cheap usb software defined radio, or is this the output of a several hundred dollar oscilloscope?