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I don't know who the audience for this article is, whether it's hardware people struggling to pass regulatory compliance, or whether it's paranoid people thinki

I don't know who the audience for this article is, whether it's hardware people struggling to pass regulatory compliance, or whether it's paranoid people thinking they can somehow escape surveillance. For passing certification, the best advice is really shielding closest possible to the source. Bury all signals, have no cables, shield the die if anything. If you can, bury the die. For escaping surveillance, make sure to never leave the shielded room, or meet with people who do. /s

gabriel34 6y ago
my isp has a built in public (captive portal) wifi network that I can't turn off. They use it to provide wifi hotspots all over the country. rf shielding is a non destructive mod I can do to block the rogue wifi
- Metacelsus 6y ago
  if this is Comcast, you can also just buy your own modem/router
  - pnutjam 6y ago
    I believe you can also turn it off in your account settings.
    - jiveturkey 6y ago
      it has been known to turn itself back on. for comcast, besides buying your own, you can also request a non-wifi router.
madengr 6y ago
Burying or shielding the die isn’t going to help, as the die isn’t large enough to radiate. The EMI typically comes from poor return paths for fast rise-time signals. Common mode (ferrite) chokes on cables help a lot, though again EMI issues are mostly due to poor circuit design and PCB layout.
jimmyswimmy 6y ago
This is a trade magazine for people who assemble systems from components. So they put a router in a box, or whatever, and need a power supply and amplifier and connectors to the outside world. The finished system needs to pass compliance testing, but they can't modify the parts they've selected - all they can do is fix the cabling and do things to the outside of the purchased components. It's kind of like EMI/EMC testing of hardware you have designed yourself; it's usually much cheaper to apply a bandaid fix (add ferrite cores, shield that cable better, terminate here not there, etc.) and add to a punch list for rev 2, than to go back to the drawing board and change the board/die/whatever. Of course if you can plan for this during design, you (and your boss/bottom line!) will be a lot happier.
- bonkabonka 6y ago
  In the mid 90s I had the dubious pleasure of being asked to repair a series of TEMPEST certified computers: standard Zenith 8086 clones (well, as standard as a Zenith got anyway) inside a massive steel chassis with all inputs/outputs wrapped around multiple ferrite cores before passing through some heavy-duty milspec connectors. Took a solid couple of minutes each machine pulling screws just to get the lid off so I could plug in a keyboard and monitor (Hercules Monochrome!) and assess the system. Took a dozen machines and made four or five working ones - lot of hard drive failures though Spinrite did manage to resurrect a couple. Still remember all those little jumper leads going from the peripheral cards through the ferrites and into the funky round connectors on the outside of the box.

gabriel34 6y ago

my isp has a built in public (captive portal) wifi network that I can't turn off. They use it to provide wifi hotspots all over the country. rf shielding is a non destructive mod I can do to block the rogue wifi

Metacelsus 6y ago
if this is Comcast, you can also just buy your own modem/router
- pnutjam 6y ago
  I believe you can also turn it off in your account settings.
  - jiveturkey 6y ago
    it has been known to turn itself back on. for comcast, besides buying your own, you can also request a non-wifi router.

madengr 6y ago

Burying or shielding the die isn’t going to help, as the die isn’t large enough to radiate. The EMI typically comes from poor return paths for fast rise-time signals. Common mode (ferrite) chokes on cables help a lot, though again EMI issues are mostly due to poor circuit design and PCB layout.

jimmyswimmy 6y ago

This is a trade magazine for people who assemble systems from components. So they put a router in a box, or whatever, and need a power supply and amplifier and connectors to the outside world. The finished system needs to pass compliance testing, but they can't modify the parts they've selected - all they can do is fix the cabling and do things to the outside of the purchased components. It's kind of like EMI/EMC testing of hardware you have designed yourself; it's usually much cheaper to apply a bandaid fix (add ferrite cores, shield that cable better, terminate here not there, etc.) and add to a punch list for rev 2, than to go back to the drawing board and change the board/die/whatever. Of course if you can plan for this during design, you (and your boss/bottom line!) will be a lot happier.

bonkabonka 6y ago
In the mid 90s I had the dubious pleasure of being asked to repair a series of TEMPEST certified computers: standard Zenith 8086 clones (well, as standard as a Zenith got anyway) inside a massive steel chassis with all inputs/outputs wrapped around multiple ferrite cores before passing through some heavy-duty milspec connectors. Took a solid couple of minutes each machine pulling screws just to get the lid off so I could plug in a keyboard and monitor (Hercules Monochrome!) and assess the system. Took a dozen machines and made four or five working ones - lot of hard drive failures though Spinrite did manage to resurrect a couple. Still remember all those little jumper leads going from the peripheral cards through the ferrites and into the funky round connectors on the outside of the box.