Christmas Tin EMP Faraday Cage

Discussion in 'Amateur Radio News' started by KG5AHJ, Dec 8, 2022.

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  1. DO1FER

    DO1FER Ham Member QRZ Page

    Good idea for owners of keyless cars to cage the always transmitting keys at home.
    W7ASA likes this.
  2. PA0MHS

    PA0MHS Ham Member QRZ Page

    I couldn't find an immediate reference to the spectrum of an EMP pulse, but I read numbers far into the GHz region. Your tin can isn't going to shield that, simply because the electrical connection between can and lid isn't good and coninuous enough. You demonstration with the FM station only proves that frequencies of around 100 MHz are shielded well enough to prevent reception. Now try the same with a cell phone. Try calling that cell phone inside the can. Chances are that you can can contact that phone. Any "opening" between lid an can will act as a half wave dipole and guide any energy on that frequency right into the can.

    That can has a vertical seam. At the seam, the lid is not closing and leaving a gap. That gap will resonate on the frequency at which it forms a half wave slot. You'd need fingerstock around the entire circumference of the lid to make it into a decent faraday cage.

    As a test, I played a youtube video on my cell phone and placed it into my microwave oven. The phone kept playing the video. The WiFi signal indicator only lost one of three bars, the cell indicator lost two of five.

    A tin can similar to your Christmas tin performed equally bad in shielding.
    I even received a whatsapp message from a friend during the test in the tin can, which ruled out that youtube was playing from a cache.
    Last edited: Dec 9, 2022
    KJ6VPY, WB9YPA, KL7KN and 3 others like this.
  3. W8JI

    W8JI Premium Subscriber QRZ Page

    EMP has gone off the charts with irrational fear. By the time a pulse is strong enough to hurt a radio laying on an open table you and everything else will be gone. Do you think your nervous system can take higher localized power density than a small HT?

    EMP can damage things with long wires that act as broadband antennas, like power and communication. The power density is too low to affect things not connected to long conductors. Cars and HT's and such, as would a regular HF radio on a desk, are pretty much immune.

    There has to be a large exposed collector of the pulse.

    Tin hats are great!
    N8VIL, KR3DX, N0TZU and 3 others like this.
  4. W7ASA

    W7ASA Ham Member QRZ Page

    I'll be happy to EMPTY all the Danish Butter Cookie tins, as my gift to preparedness.

    I do this at great personal sacrifice (sarc), as I've been on an very low carbohydrate way of eating for years and gotten rid of over one hundred pounds and more health improvements.

    73 de Ray ..._ ._
    KJ6VPY, KJ7OMD, KR3DX and 7 others like this.
  5. KQ1V

    KQ1V Platinum Subscriber Platinum Subscriber QRZ Page

    Don't give up on the diet! Let the EMP take your batteries!!
    KA0HCP, VE7KPM and KE0GXN like this.
  6. W1YW

    W1YW XML Subscriber QRZ Page

    Its a fantasy.

    Chaos will not be saved by ham radio.

    Ask Steely Dan.

    FYI, at 68 I remember Duck and Cover...thanks for the lecture.
    Last edited: Dec 9, 2022
    W4ISZ, K0IP, DL6SEZ and 1 other person like this.
  7. AE7XG

    AE7XG Ham Member QRZ Page

    Keep the popcorn for padding...
  8. NH2BV

    NH2BV Ham Member QRZ Page

    I have gotten some metal trash cans with lids (at Tractor Supply) and done pretty much the same. I have a few things in them.

    2 Baofeng tri band HT's and their chargers. 1 Tecsun PL 880 and 1 extra battery with chargers. 1 Xeigu G90 with gel battery pack. 1 30 amp linear power supply for the radios (can also be used to charge car batteries. 2 electronic control modules for Jeep Gladiator and Jeep Wrangler. A Springfied Armory XD 9 and 500 rounds of 9mm and 1000 rounds of .22 long rifle ammo and a few other goodies. I have attached the skin of the can to a ground rod independent of the radio grid. And 2 burner cell phones were just added.
    KJ6VPY likes this.
  9. KE0GXN

    KE0GXN XML Subscriber QRZ Page

    Who would have thought you could make a ham radio video with popcorn cans....

    By the same token, I can't believe people actually watch this stuff.
    KL7KN, N0TZU, K9TDW and 6 others like this.
  10. KO4TXV

    KO4TXV Ham Member QRZ Page

    Pretty cool
  11. W1YW

    W1YW XML Subscriber QRZ Page

    The lack of understanding of EMP is driving a tangential and misinformed narrative here.

    First, any tiny break in the seal, or just closing but not sealing the cover with metal, will produce a partial or full ring slot that acts as a resonant antenna-- which lets radiation in. So much for a 'Faraday Cage'...

    Seconds, RF produced by inverse Compton is--you guessed it-- RF. Albeit wideband and transient, it still is subject to wave optics and will be 'interfered' and diffracted. That means some places will be NULLED and the EMP will not have a universal destructive ability.

    Finally, ham radio is not the fantasy savior portrayed in ALAS BABYLON--at least in 2023. If EMP is widely employed your HT will not be useful to ensure the integrity of civilization.

    Cookie tins make great junk boxes but are useless as prepper material for nuclear war.

    Chip W1YW
    WB9YPA, K0LWC, W9YW and 3 others like this.
  12. AK4FU

    AK4FU Ham Member QRZ Page

    Good video, I use large military ammo cans they are water proof then wrap radios with bubble wrap and weld a lug for grounding straps, I would recommend grounding the can for better protection.
  13. W7ASA

    W7ASA Ham Member QRZ Page

    Chip said: "... ham radio is not the fantasy savior ... your HT will not be useful to ensure the integrity of civilization."

    WHERE did Frank say anything like this? You're simply making a strawman to joust with.

    de Ray ..._ ._

    Ps. Frankly, if civilization ever DOES develop systemic integrity, it would be a great improvement.
    Last edited: Dec 9, 2022
    VA7EKA and KQ1V like this.
  14. W1YW

    W1YW XML Subscriber QRZ Page

    Ham radio has no role in the event of EMP.

    Yes. That's what I said.

    I am sorry you are uncomfortable with that.

    The fact that we are showcasing an 'in event of nuclear war' 'device adds unwarranted validity to our role and abilities.

    Chip W1YW
    W8TZ and W7USD like this.
  15. G3SEA

    G3SEA Ham Member QRZ Page

    Might want to read the Trilogy ' One Second After ', ' One Year After ', 'The Final Day ' by William Fortsch ' for the Reality of such an Event.
    Yes Ham Radio does feature in the story.

    KA0USE and N1SAK like this.
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