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Thank you Missing. The lightning arrestor system on the barn actually had aluminum braided wirethat was bolted to a 5' concrete re-bar rod. It was built just before the US entered WWII so it makes sense that copper would have been in short supply at that time.
I have some heavy copper porch screen reminants from two previous renovations. I thought I could attach these to a series of wooden frames to build a faraday cage around the generator. I know the generator has a grounding rod already (runs on LP) so the grounding rod for the faraday cage should be well away from that one, is that correct?
Aluminum is nearly as conductive and has roughly the same melting point as copper, so either would work for grounding. I think your copper (or aluminum) screen should do well enough to make a cage for the generator if it's fairly fine mesh. If the generator already has a grounding rod, you can go ahead and attach your faraday ground wire to it. You don't need a separate rod since any surge from the cage will go to ground not back-travel up into the generator circuitry.
Also good to note, that cages and grounding aren't just for EMP, they work equally well to protect electronic circuitry from surges by lightning strike which can be a particular concern in rural areas where your house (or wind turbine!!) might be the highest point for acres and acres. Anyone who supplies their own power should definitely verify that their generation devices and house wiring are properly grounded, and all their important electronics (not just computers) are protected by inline surge protectors or cages. We sure don't want Gram's ventilator to get fried in a storm now do we?
That is why you want to forget about doing it the conventional way (even as it was done in the 1870s) and do a permaculture garden instead.
You can make a Faraday cage out of an aluminum trash can. There is a how to video on it on YouTube.
Quote:
Originally Posted by Mircea
What's the point?
You gonna save your cell-phone? Okay, there's no one to talk to, and no cell-phone network. You spend time and money building a Faraday Cage and your cell-phone lives an additional 6 hours until the battery dies and then that's it.
Dig a 6-inch hole, lower the cell-phone into it and give it a 21-gun salute.
For EMP? Realistically speaking in your life-time, the possibility of an EMP environment can arise from two scenarios: an EMP attack -- currently only Russia, China, France, Britain and Israel are capable of pulling that off -- and a Solar Flare, but not just any Solar Flare, an X-Class Solar Flare at least X10 or greater and also -- and this is the important part -- it would have to be accompanied by a massive proton storm (not all X-Class Flares have proton storms and even those that do are often minor or insignificant). Since the UV particles and X-rays already ionized the upper atmosphere, there's nothing to stop the protons --- they ionize the lower atmosphere all the way through to Earth.
If you want to survive...
1] Figure out the carrying capacity for your county. I finally figured out how to get to the City-Data data pages
For shats and gaggles, I'll just randomly pick a county.
Marion County, Indiana (Indianapolis) County population in July 2009: 890,879 Population density: 2248 people per square mileAgriculture in Marion County Average number of cattle and calves per 100 acres of all land in farms: 3.20 Corn for grain: 6877 harvested acres All wheat for grain: 307 harvested acres Soybeans for beans: 8136 harvested acres Vegetables: 430 harvested acres
Add up the total number of acres (ignore orchards):
6877 + 307 + 8136 + 430 = 15,750 acres
In the EMP world, you will not have chemical fertilizer, or chemical herbicides or chemical pesticides. You will be farming exactly the way people did up until the early 1870s when chemical fertilizers were first introduced. That means your crop yields will be miserable. You can expect 10 to 18 bushels of corn per acre (depending on exact location in the US, soil conditions, weather conditions etc), and half as much wheat per acre (meaning 5 to 9 bushels).
If you are a cockroach or a mouse, that is fantastic, but it sucks to be human, because you need at least 25 bushels just to live. You need 28 bushels if you want to live and farm and have the strength to defend yourself. You'll need 30 bushels to be, um, bourgeoisie.
So, as a Rule-O'-Thumb: about 2.0 to 2.5 acres per person. I use 2.5 acres per person.
15,750 acres / 2.5 acres per person = 6,300 people. That's the carrying capacity for Marion County, Indianapolis. Since there are 890,879 in Marion County, that means 884,579 people are going to die of starvation, dehydration, violence, illness, disease, injury, misadventure or their own hand. I'm real sorry about their luck.
You need to decide which group you want to be with: the 6,300 who live or the 884,579 who become worm food. If there is farmland in your community or adjacent to your community then you are in luck. All you have to do is organize protection and defend what already exists. If the farmland is on the other side of the county or something, then you'll need to get chummy with the farmers and befriend them and ingratiate yourself to them so that you will have a place to go when "it" happens. Maybe you can do a square dance or something. It would help tremendously if you can bring something to the table to show your value and worth, like a skill.
And, no, sorry, in the post-Apocalyptic World, texting is not a required skill.
2] Determine the defensive potential for the area. It is possible that you have access to a lot of farm land, but it's tactical situation is such that defending it is near impossible or would be incredibly costly. Note that in the case of Marion County, you have about 3 cows per acre of farm land, and so damn near 50,000 head of cattle. You need to protect them. They will be useful for transportation, hauling, farming and also as food and milk.
In my situation, the bulk of the farmland sits between 3 rivers. It is bounded by two minor rivers to the east and west, and a major river to the south. The only way people can get to us is from the north. Where you have rivers, you have bridges, and bridges canalize threat forces making them easy to kill. Read Sun Tzu, especially Part 12 The Attack by Fire. Fire is a cheap, easy and effective way to kill a lot of people (and troops).
If you determine your area is indefensible, then you will need to find somewhere else to go. Remember, you will be in a world that is totally hostile to you. This is not an hurricane or a tornado or an earthquake; it is the end of the world, and there is no help coming from anyone. Away from your community, you will be an outsider; an intruder; an interloper; a meddler; or as they say in Germany and the Netherlands -- ausländer -- a foreigner. They will not tolerate you, unless you have some incredible gift that no one can do without. You need some tie to that community. Maybe you have a relative living there or a friend who can vouch for you and your worthiness. If not, then try to create a tie to that community so that people know you, know your character, know what you're about and they will accept you without hesitation.
3] Plan your travel to your safe haven. For a nuclear EMP attack, it will occur during the week day, most likely late in the afternoon, around 3:00 PM (but possibly around 8:00-9:00 AM) to maximize chaos and damage. For Solar EMP, the proton storm will hit that part of the Earth facing the Sun, which means day-time. Most likely, you will be separated from your family members, meaning both spouses are at work or one at work and the other running errands and the children in school.
That is not really a problem in a rural or semi-rural area, but in urban areas it is. Violence will erupt within the hour, and travel on foot will be difficult and dangerous. You need a Rally Point; a safe place where they can get to easily where they will be met by you or others in your group, and then escorted safely to the safe haven. We use a State park that's about 4,500 acres. It's easy to get to and offers safety and concealment. Patrols will regularly run between the park and the safe haven to escort people safely.
4] Form a group. Collective security is the only way to survive. Check out all the Big Brains that are spending $Thousands on bunkers and MREs and survival garbage. They think they're going to live in their little bunker and pop the hatch a year later when the food runs out --- only to die.
Why? By that time, the real survivors will have already formed solid communities, and they will not accept outsiders for any number of reasons. They will be resentful, since you didn't get your ass in the grass with the rest of them; they will be suspicious and hostile, believing you to be spies for a group who is hostile to them; they will believe that you were expelled from a group because you are diseased, or disease carriers, or because you made trouble or worse -- you didn't pull your weight. And their situation might be very tenuous, meaning they cannot possibly afford to feed three or four or five more mouths.
So the bunker pukes spent $Thousands to die. You need at least 8 acres to ensure you can feed 4 people, and it will take 3 adults to farm 7-8 acres. Look at the historical record: 3 adults spent 10 hours per day 220-230 days per year farming 7 acres just to get enough food to feed 4-6 people. So a family of 4 with 2 children will do what? Die. There won't be anything to hunt, not that anyone would have time to hunt anyway. 10 hours a day in the fields, and what about cooking, gathering fire wood etc etc etc? They just don't have enough labor.
Every year, there are 50 Million to 300 Million weed seeds per acre of land, and this is what happens when you don't have chemical herbicides:
That's why you spend 10 hours a day 7 seven days a week in the fields.
So if you want to prep, get yourself a 9mm, a decent shot-gun and a decent rifle (and a scope), some mountain or BMX bikes, formulate a plan to get your family to safety, or to get them together, get with a group of like-minded people for collective security, find a place to call "home" and figure out how to defend it. A survival note-book would come in handy too. 3 x 5 index cards, or 5 x 8 index cards or regular paper -- doesn't matter -- just keep info on everything you think you need to know. Some examples are principles of hydraulics (making water and fluids work for you), wind/wind-mills, turbines, motors, dynamos, vacuum tube technology, farming tips, veterinarian tips (so you can keep your animals healthy), home-made weapons like mortars and recoiless rifles, grenades, etc, etc and things like that.
There will be no help.
Nuclear EMP most likely will take out most of southern Canada and northern Mexico. Solar EMP most of the Northern Hemisphere. You are on your own. The rest of the world can do nothing. Look at the Berlin Airlift. 2 Million people living in Berlin and what did it take to feed them? You would need 154 Berlin Airlifts to save the US and that is just impossible. There aren't enough aircraft on Earth. It doesn't matter. So a plane-load of food lands in the US. Now what? Nothing. That plane is stuck here, because it has no fuel to get back. Which brings up another point. The Berlin Airlift was Frankfurt to Berlin, a flight of 90 minutes, not 7 hours from London to New York (9 hours from Frankfurt to New York).
Cargo ships? Not gonna happen. For Solar EMP, the Southern Hemisphere will be lucky if it has enough food to feed its own people (they don't -- so about 10%-20% will die) and in the event of an EMP attack on the US, the rest of the world will have enough food to barely feed the rest of the world, and that's about it. So, as you can see, any attempt at resurrecting the Berlin Airlift would be equally futile.
Another issue you want to plan for is government. There will be no Continuity of Government during an EMP event, at least none worthy of mention. That means local government will have all of the power and control. The real question is, do you want local government making decisions that affect your life?
Our mayor is an incompetent buffoon. He is not even remotely capable of making decisions that are necessary and proper, or even just. I would not recognize his authority in a time of an apocalyptic crisis. If you have issues with local government, I would suggest staging a coup d'etat within the first 7 days, so that you can get organized and start effectively dealing with problems. Call it a "sudden recall election by popular referendum" if you want.
For an EMP event, Triage is an absolute necessity, and must be done immediately, as within 72 hours. In many areas of the US, Triage will mean the difference between 90% of the people dying, and 50% of the people dying. Unfortunately, local government lacks the courage to Triage. Triage is simple: tell fat-bodies to try not to die near sources of water, so as not to contaminate it. If you read the medical literature, someone used to chowing down on 3,000 to 5,000 calories per day and is suddenly cut to 900-1,200 calories per day, well, the potential for health problems is overwhelming, and you don't have the resources or time to deal with the heart attacks, organ failure and other complications. Same with people on certain types of medication. Thank them for their service to their communities, and tell them to die well. As soon as their meds run out, their health problems will flare up and you don't have the time or resources to deal with that.
Don't be so foolish as to cast away the elderly simply because they are old skins. They were born and raised in the world you are now living in; the non-technological world. Some 80 year old was repairing TV's and radios with vacuum tubes in the old days. You need him; so keep him alive as long as you possibly can. By the way, that little scrap book you should be making -- you can make vacuum tubes. That would be something useful to know.
Planning for EMP is more important than prepping, because failing to plan is planning to fail. If you do as I suggest, your odds of survival are better than 90% and will increase dramatically over time.
The first 30 days are critical. Defense is the key and that can only be done through collective security. If you want an idea of what things will be like, get the film Black Hawk Down and watch the part where the two Delta boys defend the helicopter and crew. That is exactly how it will be, except they won't be after the pilot, they'll be after the food that you are sitting on.
Those of you who live in or near urban areas, you're going to have to deal with hordes of people who are literally crazed. The Psychology of Armageddon is very different than the Psychology of Disaster. People will be driven insane; go berserk and do things they wouldn't normally do. Gangs will be a big threat early on. They are already organized, and they will expand in size quickly. Impromptu gangs will also form (because collective security works).
The winners will be those who have the best collective security and leadership. By the time you get to the 6 month mark, the population will be down to about 92 Million and most of the threats will have been eliminated. You can shift your focus from defense to survival. Once you make it through the next harvest, you can focus on re-building whatever is left.
My guess is after the 1-year mark, the rest of the world will have divvied up the US into "Zones of Protection," "Zones of Administration," "Zones of Security" or something to that effect and start moving in troops and administrator types, so you'll have to eventually plan to deal with that somehow.
Aluminum is nearly as conductive and has roughly the same melting point as copper, so either would work for grounding. I think your copper (or aluminum) screen should do well enough to make a cage for the generator if it's fairly fine mesh. If the generator already has a grounding rod, you can go ahead and attach your faraday ground wire to it. You don't need a separate rod since any surge from the cage will go to ground not back-travel up into the generator circuitry.
Quote:"Aluminum is nearly as conductive and has roughly the same melting point as copper, so either would work for grounding."
Well, aluminum only has 59% conductivity of copper (and 60% melting point), so I wouldn't say 'nearly'. Also, aluminum oxide is a good insulator, so unless you heli-arc separate pieces of the screen together, good luck maintaining a good low-resistance connection. If you attach the Al to Cu, you will need either AL-Cu wire nuts, or COPALUM. (I had to do this on a whole house).
Quote:"You don't need a separate rod since any surge from the cage will go to ground not back-travel up into the generator circuitry."
Only if the impedance of the ground rod is zero. Me thinks not.
My dad taught me to do it the old-fashioned way; Mu-metal. Thank you Bell Labs for the sheets of it you guys were throwing out. Annealed iron is not a bad choice either, and is much cheaper.
Last edited by SuperSparkle928; 03-13-2012 at 08:45 AM..
Quote:"Aluminum is nearly as conductive and has roughly the same melting point as copper, so either would work for grounding."
Well, aluminum only has 59% conductivity of copper (and 60% melting point), so I wouldn't say 'nearly'. Also, aluminum oxide is a good insulator, so unless you heli-arc separate pieces of the screen together, good luck maintaining a good low-resistance connection. If you attach the Al to Cu, you will need either AL-Cu wire nuts, or COPALUM. (I had to do this on a whole house).
Picking the fly ***** from the pepper, Al is certainly conductive enough for power company HT transmission cables. E1 of an EMP lasts a MAXIMUM of 1000nS but the EM field peaks at 200nS from detonation. That's a MHz frequency signal. Whatever increase in DC resistance is minor. Consider it a high pass filter, a single ~1/2" bolt compression connector (I actually used 5mm as the radius of contact to simplify calculation) would result in a capacitance from 4nm of alumina [standard Al oxidation layer thickness] of 1,460 uF, the Fc of that circuit is 109Hz (assuming 1 ohm total resistance). You have a single EM spike peaking at 200nS from start, and ending at 1000nS, which is a 5 MHz to 1 MHz frequency, and you're worried about a high pass circuit (one that passes high frequencies and blocks low frequencies) with Fc of 109Hz. Just to explain to the non-electrical/physics savvy this is not an issue when the frequency of the EMP is in the megahertz range, it's way above that cut off point.
Quote:
Originally Posted by SuperSparkle928
Quote:"You don't need a separate rod since any surge from the cage will go to ground not back-travel up into the generator circuitry."
Only if the impedance of the ground rod is zero. Me thinks not.
I think you mean the impedance BETWEEN ground rods is zero. It's not really relevant, the resistance to ground is so small in comparison to the resistance through a device to ground it might as well be zero. 25 ohms maximum isn't going to break the bank, try to find another tree to bark up.
Quote:
Originally Posted by SuperSparkle928
My dad taught me to do it the old-fashioned way; Mu-metal. Thank you Bell Labs for the sheets of it you guys were throwing out. Annealed iron is not a bad choice either, and is much cheaper.
So lets get this straight you complain about the conductivity of Aluminum and then talk about how iron isn't a bad choice? Confused much? Iron is only 17% the conductivity of copper, so either the conductivity of Al isn't an issue and your first comment was irrelevant, or using Fe is a really bad idea.
There is little point in using Mu-Metal, it doesn't give much of a benefit over Aluminum, Mil-Std is 40dB power reduction (remember power is 10Log, not 20Log), Aluminum is rated for SGEMP shielding against Magnetic Field, Electric Field, and Plane Wave to 40dB, which is a reduction of 1/10,000 of the original signal, given that the maximum field strength of an EMP is 50kV/m (it's a function of the atmosphere) that would result in a voltage peak behind the shielding of 5V/m, if a piece of electronics cannot survive a 5V/m peak EM burst, it's going to be dead next time it's beside something with a motor being used.
Meanwhile E2 shouldn't have much effect on your electronics, E2 is similar to being near a lightning strike all devices should be already protected against this. E3 only affects long conductors as the earths magnetosphere returns to normal, so if you're disconnected from the grid at that point, you should be fine.
Picking the fly ***** from the pepper, Al is certainly conductive enough for power company HT transmission cables.
Aluminum is cheap compared to copper. We are talking quality, not price.
E1 of an EMP lasts a MAXIMUM of 1000nS but the EM field peaks at 200nS from detonation. That's a MHz frequency signal. Whatever increase in DC resistance is minor. Consider it a high pass filter, a single ~1/2" bolt compression connector (I actually used 5mm as the radius of contact to simplify calculation) would result in a capacitance from 4nm of alumina [standard Al oxidation layer thickness] of 1,460 uF, the Fc of that circuit is 109Hz (assuming 1 ohm total resistance). You have a single EM spike peaking at 200nS from start, and ending at 1000nS, which is a 5 MHz to 1 MHz frequency, and you're worried about a high pass circuit (one that passes high frequencies and blocks low frequencies) with Fc of 109Hz. Just to explain to the non-electrical/physics savvy this is not an issue when the frequency of the EMP is in the megahertz range, it's way above that cut off point.
My point was electrical resistance caused by oxidation.
(BTW, I have a PhD in high energy physics from an Ivy league standing over my shoulder, and I can't get him to stop laughing ). Was YOUR thesis advisor on the Manhattan project? (hint, his advisor was the head of the Fat Man team). He has been doing EMP research for over 40 years.
Mu-metal is DESIGNED for low-frequency magnetic fields. geez... (and is only about 16% iron) It is mostly nickel.
I think you mean the impedance BETWEEN ground rods is zero. It's not really relevant, the resistance to ground is so small in comparison to the resistance through a device to ground it might as well be zero. 25 ohms maximum isn't going to break the bank, try to find another tree to bark up.
I will bark up another tree. You need to read about ground loops.
So lets get this straight you complain about the conductivity of Aluminum and then talk about how iron isn't a bad choice? Confused much? Iron is only 17% the conductivity of copper, so either the conductivity of Al isn't an issue and your first comment was irrelevant, or using Fe is a really bad idea.
Let's compare the magnetic permeability of mu-metal to most metals you can find. Let me know when your homework is done.
There is little point in using Mu-Metal, it doesn't give much of a benefit over Aluminum, Mil-Std is 40dB power reduction (remember power is 10Log, not 20Log),
Logarithms were taught in high school...
I used mu-metal because it was free, and better than Al or Cu.
Aluminum is rated for SGEMP shielding against Magnetic Field, Electric Field, and Plane Wave to 40dB, which is a reduction of 1/10,000 of the original signal, given that the maximum field strength of an EMP is 50kV/m (it's a function of the atmosphere) that would result in a voltage peak behind the shielding of 5V/m, if a piece of electronics cannot survive a 5V/m peak EM burst, it's going to be dead next time it's beside something with a motor being used.
Meanwhile E2 shouldn't have much effect on your electronics, E2 is similar to being near a lightning strike all devices should be already protected against this. E3 only affects long conductors as the earths magnetosphere returns to normal, so if you're disconnected from the grid at that point, you should be fine.
Mine in red.
Last edited by SuperSparkle928; 03-13-2012 at 05:01 PM..
Aluminum is cheap compared to copper. We are talking quality, not price.
Yes but you're talking Mu-Metal, which you got for free, if we're not discussing price then I'd recommend silver. But that's impractical. Aluminum is a perfectly adequate compromise of price and functionality.
Quote:
Originally Posted by SuperSparkle928
My point was electrical resistance caused by oxidation.
(BTW, I have a PhD in high energy physics from an Ivy league standing over my shoulder, and I can't get him to stop laughing ). Was YOUR thesis advisor on the Manhattan project? (hint, his advisor was the head of the Fat Man team). He has been doing EMP research for over 40 years.
Then your PhD's prof should be well aware that the DC resistance is irrelevant because it requires you to consider the actual moving field (no moving field and there's no problem from voltage induced, because there is no voltage induced). Are you sure he's not laughing at you? My PhD Prof was Janet Carter Cavendish Labs Cambridge, maybe you've heard of her, maybe not, of course singing Ivy League doesn't impress (for obvious reasons), an I've never met a Yale grad worth a damn, or anyone outside of Harvard Law or Business, Princeton's only any use for Military officers in my experience. In my last line of work I'd take someone from CM, FIT, or Stanford way ahead of an Ivy Leaguer.
BTW Your PhD's dates don't add up, if he's been researching EMP for 40 years then that's back to 1972, claimed advisor of your PhD was dead in 1967, but pretty much stopped teaching by 1954. So either he's been researching EMP for nearly 60 years making him at least 80 years old (and I'll be honest I can't see what there is to research about EMP for 60 years), or his advisor wasn't who he's claiming it was. You might want to look into that.
Quote:
Originally Posted by SuperSparkle928
Mu-metal is DESIGNED for low-frequency magnetic fields. geez... (and is only about 16% iron) It is mostly nickel.
Indeed it was which was why I was surprised you mentioned it, it's commonly used to suppress static magnetic fields. Everyone has some in their PC Hard drives as shielding.
Quote:
Originally Posted by SuperSparkle928
I will bark up another tree. You need to read about ground loops.
Erm... No...
Actually a single point ground cannot form a ground loop, multiple grounds are needed. I think you're confused on this. If I have a ground stake (single point ground, or multiple stakes all interconnected), it's potential to absolute ground is some value, if I have two stakes (only with ground connecting them), then the potential between each one and absolute ground may not be the same, it depends on soil resistance and water content to name two things (plus there is differences in the actual cabling, rod itself, and it's electrical coupling), that is a ground loop, thus if I have two discrete ground stakes and some big honking EM field flashing past at near the speed of light, there may very well be a couple of thousand volts and couple of thousand amps difference between those two stakes at some point in time (i.e. the plane wave has passed ground 1 but not yet hit ground 2), so two pieces of equipment connected to two grounds that can be brought into contact via some organic material can result in death. That's Electrics 101, and why according to code all grounds used in the same location must be interconnected. This is precisely why a single point ground is preferable.
Quote:
Originally Posted by SuperSparkle928
Let's compare the magnetic permeability of mu-metal to most metals you can find. Let me know when your homework is done.
I don't need to, mumetalis not needed to shield against EMP, ANY adequate conductor can form a shielding enclosure and provide adequate protection. To explain, you're defending mumetal, but there's no need to defend it, it should work perfectly well as an enclosure, but so would Aluminum. Aluminum, MuMetal, and SuperAlloy are all rated to Mil-Std for EMP shielding.
Quote:
Originally Posted by SuperSparkle928
Logarithms were taught in high school...
I used mu-metal because it was free, and better than Al or Cu.
You know you need to get your story straight, because the first comment was Aluminum was cheap, not the best, and now you're saying you use mumetal because it's free, which is cheap, for an EMP it is not the best, that would be silver since it has the highest conductivity of any metal, and that's what will provide the protection needed, because that's the thing that's preventing the electromagnetic field entering the enclosure with enough energy to cause any permanent damage.
Yes but you're talking Mu-Metal, which you got for free, if we're not discussing price then I'd recommend silver. But that's impractical. Aluminum is a perfectly adequate compromise of price and functionality.
Then your PhD's prof should be well aware that the DC resistance is irrelevant because it requires you to consider the actual moving field (no moving field and there's no problem from voltage induced, because there is no voltage induced). Are you sure he's not laughing at you? My PhD Prof was Janet Carter Cavendish Labs Cambridge, maybe you've heard of her, maybe not, of course singing Ivy League doesn't impress (for obvious reasons), an I've never met a Yale grad worth a damn, or anyone outside of Harvard Law or Business, Princeton's only any use for Military officers in my experience. In my last line of work I'd take someone from CM, FIT, or Stanford way ahead of an Ivy Leaguer.
Remember, there are 8 Ivy's.
Cornell is no slouch of a university (an Ivy), nor is MIT or Stanford (which aren't). The latter two I know well. Been there, done that.
BTW Your PhD's dates don't add up, if he's been researching EMP for 40 years then that's back to 1972, claimed advisor of your PhD was dead in 1967, but pretty much stopped teaching by 1954.
Claimed advisor died Apr 22, 2005. I met him numerous times. Said advisor's PhD candidate's line of work was initially superconductors, in the 60's. A stack of patents on them. Then switched to EMP research.
So either he's been researching EMP for nearly 60 years making him at least 80 years old (and I'll be honest I can't see what there is to research about EMP for 60 years), or his advisor wasn't who he's claiming it was. You might want to look into that.
You are correct, he is in his 80's. As I stated, he was well into his career, after superconductor research, to evaluate EMP (mostly for rad-hardening telecom equipment, and shielding for ultra-high security communication networks). I don't really need to look into it, as I have 50% of his genes, and sort of hung around with him since I was born.
Fermi was concerned about EMP in '45.
(totally off-topic: my 3 chihuahuas are named Fermi, Tesla and Joule )
Indeed it was which was why I was surprised you mentioned it, it's commonly used to suppress static magnetic fields. Everyone has some in their PC Hard drives as shielding.
[/i]Erm... No...
Actually a single point ground cannot form a ground loop, multiple grounds are needed. I think you're confused on this.
Not confused in the least. The amplifiers I have built, which have noise figures about the same as a resistor, invoke some paranoia in many engineers about ground loops.
If I have a ground stake (single point ground, or multiple stakes all interconnected), it's potential to absolute ground is some value, if I have two stakes (only with ground connecting them), then the potential between each one and absolute ground may not be the same, it depends on soil resistance and water content to name two things (plus there is differences in the actual cabling, rod itself, and it's electrical coupling), that is a ground loop, thus if I have two discrete ground stakes and some big honking EM field flashing past at near the speed of light, there may very well be a couple of thousand volts and couple of thousand amps difference between those two stakes at some point in time (i.e. the plane wave has passed ground 1 but not yet hit ground 2), so two pieces of equipment connected to two grounds that can be brought into contact via some organic material can result in death. That's Electrics 101, and why according to code all grounds used in the same location must be interconnected. This is precisely why a single point ground is preferable.
Preaching to the choir.
(in blue) Mostly. When installing an outdoor hot tub, I encountered the statement in the electrical code that there be an 8-foot ground rod within a certain distance of the tub, (and that is not the same as the house ground rod). Ground loop city. Argued with the inspector about it, I lost. Even if the separate grounds are interconnected with metal wire, the wire does not have zero resistance, and can create an offset voltage between the two ground.
My interpretation of the previous postings in this thread indicated that there was a ground rod next to the generator, and another one for the main house. Perhaps clarification is needed.
[/i]I don't need to, mumetalis not needed to shield against EMP, ANY adequate conductor can form a shielding enclosure and provide adequate protection. To explain, you're defending mumetal, but there's no need to defend it, it should work perfectly well as an enclosure, but so would Aluminum. Aluminum, MuMetal, and SuperAlloy are all rated to Mil-Std for EMP shielding.
[/i]
You know you need to get your story straight, because the first comment was Aluminum was cheap, not the best, and now you're saying you use mumetal because it's free, which is cheap, for an EMP it is not the best, that would be silver since it has the highest conductivity of any metal, and that's what will provide the protection needed, because that's the thing that's preventing the electromagnetic field entering the enclosure with enough energy to cause any permanent damage.
As silver may be the best electrical conductor, it also oxidizes (as does aluminum, so as being the 'best', I would argue not in the practical sense.
You won't see any of my circuit boards with silver-plated connectors. A recipe for failure. We use gold for a reason.
Mine in red.
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Thank you, thank you. thank you.
He has been doing EMP research for over 40 years.
