EMI / RF / Shielding Experiments with aluminum screen wire mesh and galvanized steel box

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Problem: video switch (ATEM Television Studio failed probably due to rf/emi).
hypothesized solution: shield all cables and whole device.

findings on cables:

  1. all hdmi cables are shielded. i opened all cables from camera manufacturers (panasonic) and also all cables from CDR-King, they all have shields.  some of them also have shields in individual cables, aside from the main foil shielding all cables.  some of them, the long cables, have aluminum shield inside and mesh shield outside.
  2. all power cables are not shielded.  including 12v cables, 220v cables, 5v cables.
  3. UTP is of course Unshielded.  STP is shielded.
  4. need to check USB cables if shielded. (it is shielded)

experiment 1 - metal sheet box shield VS wifi:

half day of metalwork - not so nice
first third is outside metal shield
center part is inside shield
last third is outside shield

experiment 2 - aluminum screen 1 layer VS wifi:

aluminum screen rolled (1 layer only)
over cellphone
first, mountains are outside screen
2nd, hills is inside shield but not clipped sides
3rd, valley is when sides are well clamped
4th, cliff is when cellphone is taken out of screen

experiment 3 - aluminum screen 5 layers VS wifi:

screen shield,
rolled 5 layers over device
first red moutain is with five layers but sides are not well clipped,
center valley is when all sides are well clipped,
last part mountains is when device removed from mesh roll

FINDINGS:

  1. (well-clipped) screen roll is better (than not well clipped) galvanized metal box.  well clipped means all sides and holes are covered.
  2. easier to ventilate aluminum screen roll than galvanized metal box.

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