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


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.

Popular posts from this blog

Cooking on Sabbath for Seventh-day Adventists - Bible, EGW/SOP, Church Documents

Image
Cooking on Sabbath for Seventh-day Adventists - Bible, EGW/SOP, Church Documents Bible Manna in Exodus  “Tomorrow is the rest of the holy Sabbath unto the Lord: bake that which ye will bake today, and seethe that ye will seethe ; and that which remaineth over lay up for you to be kept until the morning.”  16:27 (NIV)  Nevertheless, some of the people went out on the seventh day to gather it, but they found none.   28  Then the  Lord  said to Moses, “ How long will you [ c ]  refuse to keep my commands  and my instructions?   29  Bear in mind that the  Lord  has given you the Sabbath; that is why on the sixth day he gives you bread for two days. SOP / EGW Those who neglect to prepare for the Sabbath on the sixth day, and who cook food upon the Sabbath, violate the fourth commandment, and are transgressors of God's law . All who are really anxious to observe the Sabbath according to the commandment, will not cook any food upon the Sabbath. They will, in the fear
Read more

Sabbath Cooking Excuses Investigated

Image
Sabbath Cooking Excuses Investigated Copyright 2016 Winelfred G. Pasamba Foreword "God means that testing truth shall be brought to the front, and become a subject of examination and discussion, even if it is through the contempt placed upon it. The minds of the people must be agitated. Every controversy, every reproach, every slander, will be God's means of provoking inquiry, and awakening minds that otherwise would slumber."—Testimonies for the Church 5:453. ChS 159.2 This is a very difficult, very shaking, very testing, very new and controversial (for many who are not oriented) topic and I request the readers not go to Chapter 3 & 4 unless they have read Chapter 1 & 2.  If you go directly to Chapter 3, you probably will be highly uncomfortable if you have no testimony of avoiding cooking on the Sabbath. Readers need utter humility and gratitude-to-God, for this material not to offend them.  Love for God must be more than love for food, love for comfo
Read more

Wearing Makeup -- Related Quotes from Bible and EGW Writings

Wearing Makeup -- Related Quotes from Bible and EGW Writings Lev 19:28 Ye shall not ... print any marks upon you : I am the LORD. Jer 4:30 And when thou art spoiled, what wilt thou do? Though thou clothest thyself with crimson, though thou deckest thee with ornaments of gold, though thou rentest thy face with painting , in vain shalt thou make thyself fair; thy lovers will despise thee, they will seek thy life. 1Pet 3:3 Whose adorning let it not be that outward adorning of plaiting the hair, and of wearing of gold, or of putting on of apparel; 1Pet 3:4 But let it be the hidden man of the heart, in that which is not corruptible, even the ornament of a meek and quiet spirit , which is in the sight of God of great price . 2Ki 9:30 And when Jehu was come to Jezreel, Jezebel heard of it; and she painted her face , and tired her head, and looked out at a window. 1Tim 2:9 In like manner also, that women adorn themselves in modest apparel , with shamefa
Read more