I need help building a Faraday shield. - Page 1
Forum section: electronics / beginners

author: novicefedora
author_rank: Contributor
timestamp: July 22, 2020, 09:56:10 pm
content: I have a mesh which I'm not sure if it will be good for Faraday shield. Disregarding that, I'm unable to come up with a way to attach the mesh without reducing it's effectiveness. If I were to use nails, the nails will create holes in the mesh. I don't have a stapling gun and I'm not sure if it will be better than nails. Another problem I have is the mesh's breadth is around 5 feet, the Faraday enclosure I'll be building would be about 10 feet, so I have to use two layers of the mesh to cover 10 feet, one at top and another at bottom, if I do this, there will be a gap between two layers, how can I attach this gap to ensure continuity?

author: bob91343
author_rank: Super Contributor
timestamp: July 22, 2020, 10:49:07 pm
content: Can you solder the junctions? If it's a mesh, there is a strong possibility that the interstices are not making good contact so it may not be suitable as a shield. It's a lot of effort to solder every crossing. If it's expanded metal, that insures its integrity.

author: novicefedora
author_rank: Contributor
timestamp: July 22, 2020, 10:54:41 pm
content: Quote from: bob91343 on July 22, 2020, 10:49:07 pmI can try to solder but it'll take a long time and may not be so durable.This is the first time I'm hearing about expanded metal, does it also have holes in 1mm sizes? How is that different than mesh?How can I attach the mesh to a wooden frame? If the layers overlap, will it ensure continuity?

author: bob91343
author_rank: Super Contributor
timestamp: July 23, 2020, 02:46:31 am
content: Expanded metal is sheet metal with a pattern of holes or slots punched, then stretched so as to open the holes. It's better than screen and stronger as well. It's one piece so has the integrity you need. It's common stuff but I don't know about getting it in copper.If you want to overlap two layers, you can solder. Attaching to a wooden frame only requires tacks or staples.

author: Mechatrommer
author_rank: Super Contributor
timestamp: July 23, 2020, 02:56:06 am
content: stitch with conductive thread, find whatever flexible you can find there, stripped from wires strand, cloth hanging cable whatever. naked, not insulated, so they can make conduction with each other.

author: novicefedora
author_rank: Contributor
timestamp: July 23, 2020, 03:05:24 am
content: Quote from: bob91343 on July 23, 2020, 02:46:31 amIf I use staples, won't those create a hole?

author: Brumby
author_rank: Unknown
timestamp: July 23, 2020, 04:10:52 am
content: Up to what frequency do you want this Faraday cage to work?

author: gbaddeley
author_rank: Regular Contributor
timestamp: July 23, 2020, 05:06:55 am
content: Quote from: Brumby on July 23, 2020, 04:10:52 amYes, that determines the min / max constraints on size of holes in the mesh.

author: novicefedora
author_rank: Contributor
timestamp: July 23, 2020, 05:33:52 am
content: Quote from: Brumby on July 23, 2020, 04:10:52 amI want to block up to 5G frequencies.

author: Brumby
author_rank: Unknown
timestamp: July 23, 2020, 09:41:41 am
content: From a 10 second Google search:"The rule of thumb for a Faraday cage is that the openings should be no larger than 1/10th of the wavelength"

author: novicefedora
author_rank: Contributor
timestamp: July 23, 2020, 07:55:36 pm
content: Quote from: Brumby on July 23, 2020, 09:41:41 amThe problem I have is I was sold mesh with 1mm hole size claiming it was made with Aluminum, when I wrapped it around a smartphone and called the smartphone, the call went through.A user on ElectronicsPoint.com suggested I first place a smartphone in a metal biscuit box, close and call the smartphone inside it, if the call doesn't get through I drill a hole in the metal container and place a piece of my mesh on that hole and see if the call get through with the mesh on the hole. So I tried this method and even then the call got through.I'm unable to understand what the problem could be, have I been cheated?

author: tkamiya
author_rank: Super Contributor
timestamp: July 23, 2020, 10:35:46 pm
content: It'll also depend on how good of a shielding you need. 5G frequency is really a wide term as well. The actual frequency is from hundreds of MHz into dozens of GHz.This is really not a DIY project without an ability to measure and spend sizable amount of money. Otherwise, you can only do what your budget allows. There are shield boxes that use metal inner and outer casings and gaps are filled with ferrite like material.About "wrapping".... you may have just created an antenna by doing it. The real antenna could couple with the foil and radiate. What's the purpose of this project?What was the signal level before you wrapped your phone? If you are close to towers, there's not much you can do, besides going full blown.

author: novicefedora
author_rank: Contributor
timestamp: July 23, 2020, 11:18:25 pm
content: Quote from: tkamiya on July 23, 2020, 10:35:46 pmI need a shielding which will reduce the signal strength to insignificance. What equipment would I need to measure and how money am I likely to require spending?There is an implant in my body, possibly in my ear region, which emits sounds and transmits information about neural impulses sent to my throat and vocal cords, I need to prevent it from send and receiving any information.I didn't measure the signal level, if I place it within a metal box, it is impossible for me to see the signal strength or operate the phone. What would a full blown setup be like?

author: tkamiya
author_rank: Super Contributor
timestamp: July 23, 2020, 11:30:57 pm
content: Exactly! All that is part of a big problem. How do you reduce the signal to INSIGNIFICANCE. How do you measure what's inside when it doesn't emit anything?To answer this for yourself, you'll have to know what is "insignificant" is. Who's receiving the information? What are the sensitivities of this receiving apparatus? Then you'll have to know how much this device is transmitting. You'll have to reduce the signal level to below that of recipient's capability.There are companies all over the world that does certification of radio emissions. They have shielded room with antennas and measuring equipment inside. These are completely separated from outside for practical purposes.You can look up "EMC test chamber." Here's an example:https://www.isotechinc.com/radio-frequency-and-electromagnetic-testing-chambers/Also, there are boxes I mentioned. They have ports for connection to outside. Shielding this connection well enough is another issue. You can also find these under the same google search.Good luck!

author: novicefedora
author_rank: Contributor
timestamp: July 24, 2020, 01:24:07 am
content: What equipment would I require to measure at what frequencies it is emitting and what is the strength of those frequencies?

author: tkamiya
author_rank: Super Contributor
timestamp: July 24, 2020, 01:55:52 am
content: So you are looking for a hidden device that emits some sort of signal. Then process will be to verify the existence of such signal or device first. Then you will need some sort of receiver to actually listen and analyze the content of the signal.That can be anything from wide band receiver to spectrum analyzers.Tell us how you know you have such device. What are the evidence and circumstances brought you to this conclusion. Who might have been responsible. That will be a good start.Seems I am not privy to the privileged of having such information. Have you consulted any professionals in the field? Medical community might be able to assist you with initial observations and suggestions. That's what I would try if I were to believe such situation exists.

author: novicefedora
author_rank: Contributor
timestamp: July 24, 2020, 02:53:15 am
content: Quote from: tkamiya on July 24, 2020, 01:55:52 amThere were few instances years back, when I woke up with a stiff neck only on 1 side. It was always the same side. No, I haven't consulted any medical profession, but they could be bribed to lie. The people who went to great lengths to implant might control the doctors, staff too.Then there is this incident:QuoteThere are many such incidents which cannot be explained by my normal thought pattern and everyday reality.

author: tkamiya
author_rank: Super Contributor
timestamp: July 24, 2020, 04:03:41 am
content: I have still neck issue all the time.... I feel your pain! Seeing same thing over and over is not that unusual, at least for me. I never connected one and the other together though. It got to be frightening.While it is true that anyone can tell a lie, data is hard to fake. If you believe there is something in your neck, why don't you have your doc (you have a regular doctor, correct) take an Xray and have him SHOW YOU the xray? Besides, it deeply concerns you. You have to start somewhere. Whether you accept his/her answer is entirely up to you. I and others here can answer technical questions but what you are looking for is beyond that. Internet is probably not the right place for a "personal" care.Take care...

author: novicefedora
author_rank: Contributor
timestamp: July 24, 2020, 06:52:55 am
content: Quote from: tkamiya on July 24, 2020, 04:03:41 amI had to tell you about implant because you asked me what is the purpose of the project.By data you mean X-ray or other types of scans, if they can get a doctor to lie, they can also fabricate false x-rays and scan information. My queries here initially were only related to technicalities of the construction. Obviously I'll get it removed but only by a medical staff who will be honest and whom I can trust, it'll take a long time, and I may even have to travel out of the country for that, a country which doesn't have connections with 3 letter agencies. (That would be difficult, North Korea comes to mind but even that could all be a ruse)Until then I can at least try mitigating it, that is what I'm hoping to do with this shield and that is also the reason for asking how to build a signal jammer which will block custom frequencies, for that I first need to identify what frequencies the implant is using to transmit and receive information, I suspect it could be GSM and similar frequencies because I get a lot of interference when I'm talking on the cell phone, when I check signal strength, it is always full.I'm not expecting personal care from anyone on the internet, I know most users here can only answer queries and that is only what I require.

author: Mechatrommer
author_rank: Super Contributor
timestamp: July 24, 2020, 07:17:41 am
content: https://en.m.wikipedia.org/wiki/Electromagnetic_shieldingKeyword... magnetic permeability... use mu metal, not biscuit metal.. normal metal only block rf at some degree, sometime graded in dB vs freq plot, even if fully solid enclosure with no hole... you need several layers of enclosure to further block.

author: novicefedora
author_rank: Contributor
timestamp: July 24, 2020, 04:49:12 pm
content: Quote from: Mechatrommer on July 24, 2020, 07:17:41 amThe biscuit metal box did manage to block the rf signals to the phone but to verify if the mesh I have will work, I drilled a small hole in the metal and placed the mesh on it, and called it again, with this mesh on it the calls went through.

author: sokoloff
author_rank: Super Contributor
timestamp: July 25, 2020, 09:48:44 pm
content: I took a few pics of a mobile phone test cage I have in case they help.

author: sokoloff
author_rank: Super Contributor
timestamp: July 25, 2020, 09:49:26 pm
content: Another angle

author: novicefedora
author_rank: Contributor
timestamp: July 26, 2020, 10:33:29 pm
content: Quote from: sokoloff on July 25, 2020, 09:48:44 pmSo you are saying the frame also has to be made with a conductive metal? The mesh seems all crumpled.

author: sokoloff
author_rank: Super Contributor
timestamp: July 26, 2020, 11:41:19 pm
content: Well, yes. That box is designed to isolate mobile devices from the outside world to test in a controlled environment. Therefore, it is a complete cage of conductive material.The mesh provides a way to reach in and manipulate the device under test as well as (with some difficulty) to read the screen.

author: Brumby
author_rank: Unknown
timestamp: July 26, 2020, 11:50:51 pm
content: The frame does not have to be made of conductive material - BUT - the conductive covering must cover the entire structure. Whether that be a single piece of mesh wrapped around or several panels.What you also must ensure is that the coverage is continuous. Having breaks (for example, around a door) is not going to provide proper shielding. If there are gaps, then these should be bridged so that there is a continuous conductive capsule around the DUT.

author: novicefedora
author_rank: Contributor
timestamp: July 27, 2020, 12:42:31 am
content: Quote from: Brumby on July 26, 2020, 11:50:51 pmWhat can I do to ensure continuity around a door? If I use a door with hinges it will have to rotate, so there cannot be continuity when open, if it is closed, the door's mesh would touch the frame's mesh and form continuity.

author: sokoloff
author_rank: Super Contributor
timestamp: July 27, 2020, 12:46:30 am
content: The one I took a pic of has a metallized gasket that is crushed against the flat face when the hinge is closed. Then, there’s a large over-center clamp mechanism to put a set (and high) pre-load on that gasket.

author: novicefedora
author_rank: Contributor
timestamp: July 27, 2020, 08:27:14 am
content: Quote from: sokoloff on July 27, 2020, 12:46:30 amI cannot see the gasket and over-center clamp on in the photos you posted. Can you post photos of those?

author: sokoloff
author_rank: Super Contributor
timestamp: July 27, 2020, 03:02:22 pm
content: I will try to remember to take a few more detailed pictures the next time I'm at that location.That will quite possibly be end of next week.

author: gfmucci
author_rank: Regular Contributor
timestamp: July 29, 2020, 08:56:32 pm
content: Read the specs on this and see if this will help...https://www.amazon.com/gp/product/B07JGJ897T/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1EMF Meter,Advanced GQ EMF-390 Multi-Field Electromagnetic Radiation 3-in-1 EMF ELF RF meter, 5G Cell Tower Smart meter Wifi Signal Detector RF up to 10GHz with Data Logger and 2.5Ghz Spectrum Analyzer