4 ms·

My kids have a super cheap battery driven disco ball thingy that completely obliterates WiFi and cellular when it’s on. Amazing what 1.5v and an unshielded mot

My kids have a super cheap battery driven disco ball thingy that completely obliterates WiFi and cellular when it’s on. Amazing what 1.5v and an unshielded motor can do! Took me a long time to work out what was going on. When we worked out the correlation it was super easy to test though. And yeah, turning on that little disco globe just killed the WiFi.

suzzer99 5y ago
Reminds me of many years ago when my coworker's monitor was flickering. So we replaced the monitor. Same problem. We replaced cords. Same problem. We replaced the computer. Same problem. Eventually we put his monitor and computer on a cart with an extension cord and wheeled it into the hallway. Problem went away. It turned out his room had bad electrical shielding and magnetic interference was janking up the CRT monitors.
- andy_ppp 5y ago
  I would say the monitor had the bad electrical shielding…
  - LeonM 5y ago
    Actually both. When you produce electronics, each device must pass an electromagnetic compatibility (EMC) test before you are allowed to legally sell it. It test both the electromagnetic emission and the electromagnetic immunity of the device. So not only shouldn't the device emit more than a certain level of EM power, but it must also be able to withstand a certain field strength without losing functionality.
    - wizzwizz4 5y ago
      There's a limit to how much magnetic field strength a CRT can withstand, unless you shield it well enough that the screen is obscured.
  - suzzer99 5y ago
    The monitor was fine in other rooms. We brought in a magnetometer and it went off the charts on the wall near the electrical box in that room. The landlord of the building eventually had it fixed.
post_break 5y ago
When working for an ISP I was told a story of a huge amount of noise getting into the system sporadically on a node in a neighborhood. Happened during a certain time only about once a week and only for about 15-20 minutes. They finally tracked it down to some guys electric weed wacker. They bought him a brand new one and took the offending one. I guess it was bringing the service to its knees every time he used it.
geon 5y ago
I used to play GSGO. I noticed that using the youtube app on a certain iphone 4s would completely kill my latency, adding about 200 ms.

suzzer99 5y ago

Reminds me of many years ago when my coworker's monitor was flickering. So we replaced the monitor. Same problem. We replaced cords. Same problem. We replaced the computer. Same problem. Eventually we put his monitor and computer on a cart with an extension cord and wheeled it into the hallway. Problem went away. It turned out his room had bad electrical shielding and magnetic interference was janking up the CRT monitors.

andy_ppp 5y ago
I would say the monitor had the bad electrical shielding…
- LeonM 5y ago
  Actually both. When you produce electronics, each device must pass an electromagnetic compatibility (EMC) test before you are allowed to legally sell it. It test both the electromagnetic emission and the electromagnetic immunity of the device. So not only shouldn't the device emit more than a certain level of EM power, but it must also be able to withstand a certain field strength without losing functionality.
  - wizzwizz4 5y ago
    There's a limit to how much magnetic field strength a CRT can withstand, unless you shield it well enough that the screen is obscured.
- suzzer99 5y ago
  The monitor was fine in other rooms. We brought in a magnetometer and it went off the charts on the wall near the electrical box in that room. The landlord of the building eventually had it fixed.

post_break 5y ago

When working for an ISP I was told a story of a huge amount of noise getting into the system sporadically on a node in a neighborhood. Happened during a certain time only about once a week and only for about 15-20 minutes. They finally tracked it down to some guys electric weed wacker. They bought him a brand new one and took the offending one. I guess it was bringing the service to its knees every time he used it.

geon 5y ago

I used to play GSGO. I noticed that using the youtube app on a certain iphone 4s would completely kill my latency, adding about 200 ms.