When using lightning as an EMP comparision, keep in mind that the field strength of a high-altitude NEMP event as envisioned by preppers is simulated by a medium size lightning strike 3/8 of a mile away with no direct connection to you via a power line or something like that.

Higher EMP field strengths are from being in proximity to a ground or air burst nuclear detonation, at which point EMP will be the least of your problems.

So I guess my medium size lightning strike 20 yards from my house puts me in the been there done that club. My biggest expense was the cost of having the tree cut down, and it was not insignificant. The $80 for the incoming power filter on my 756 was minor in comparison (my antenna was disconnected but my radio was connected to my power supply, that was the loop that received the EMP).  Where the strike re-emerged from the roots was impressive. It thru debris all over my neighbor's deck and back steps.

20 yards puts you within the range of notable magnetic field strengths, not just E-field. If you're that close to a strike, you need magnetic shielding in addition to electrical. IE, you need a steel enclosure. You got a whole bunch of E-field charge too

That's a great document in that it provides the best, unclassified data I've seen on EMP levels and waveforms. As a guide to the robustness of equipment and infrastructure though it's pretty poor. It's recommendations are mostly pro forma. However, where it does make specific recommendations they are agreeably mundane, such as in their discussion of using Bourns GDT and the like. I.e. even this document does not call for extreme measures of protection or anything outlandish.

To be perfectly transparent, I've not read a single one of his "claims". I've only judged him by the quality, type, ad copy and pricing of the product websites he is associated with. From that perspective, it all appears to be the work of a snake oil salesman. Those websites prey on the fears and ignorance of the public to sell them overpriced stuff, much of which they don't need, and which is often inferior to other offerings. This has been pointed out multiple times by more than one poster in this thread.

I'm sure he's a very smart, well educated person. Perhaps well respected in his primary field of endeavor. But anyone who preys upon the fear and ignorance of the general public they way it is done on the DP website is not to be respected. Or, for that matter, it's even worse on the "EMF Beacon" website: https://emfbeacon.com/products/emf-beacon. For all that is holy, it is known beyond any shadow of a doubt now that living under power lines, riding electric trains, living in an ocean of Wi-Fi and cellular, and all of the other things that expose folks to common, every day electromagnetic fields is not harmful! Yet that web site preys on that fear and ignorance. It is morally reprehensible.

He's smart all right. Foxy smart. At this point he might take home more money from his publishing and product sales than he does from his government service NASA salary.

Yes, our homestead took two strikes within two seconds. The first hit the power pole directly in front of the house, about 300 meters distant. The second strike hit the top of the well head about 30M from the house. In both cases the house had excellent power line entry point protection, and that protection survived. The only other entry point to the house is an optical fiber. The well pipe is plastic. Thus all damage in the house was almost certainly caused by lighting EMP (LEMP).

Of the four large screen TVs in the house, 3 TVs lost all but one HDMI input. All TVs were off, all TVs were plugged into a UPS, most HDMI ports did not have anything attached. Thus my previous comment about HDMI ASICs being very vulnerable. Of the 6 computer monitors in the house with HDMI, none were effected. The fourth TV, a Panasonic, also was completely unaffected. All consumer equipment with HDMI outputs was unaffected. Thus there seems to be a systematic issue with HDMI inputs on consumer TV equipment.

The other major systematic issue in the house involve long runs (>30M) of CAT5 Ethernet. I have six of those runs. Four go from a POE switch to POE WAPs. Those all survived and I can only guess it's because the POE circuitry provides some measure of protection. On the other two runs I lost all NICs at both ends. On one run it was a PC NIC and a ham radio NIC (ANAN-8000DLE). On the other run it was a router NIC and the fiber ONT NIC.

To date I've added Ethernet surge suppression onto all long runs (I had considered fiber, but there were reasons it was impractical) and HDMI surge protection (but I'm not confident that will help since both plugged and unplugged ports were killed).

The lightning also fracked my well (the pump motor survived!) but that's not really an EMP-related issue.

I thought the EMP-beacon was rather interesting although not particularly useful. It's kind of like "Hey, something just happened that was strong enough to set me off. Sucks to be you unless you had protection already."

I liked that CISA document because it not only had a lot of good explanatory things regarding both man-made as well as natural phenomenon but also the notion of "levels of protection" concept. You don't have to build a hardened military bunker to keep most of your important stuff protected. It looked to me that their levels 1 and 2 were easily achieved without a huge expense. Level 3 seemed like maybe good for state and local EOC kinds of things with Level 4 being Uncle Sam kind of money required.

On the topic of your house power-line protection, could you say a little more about that? One of the things Art recommends but doesn't sell himself is a whole-house surge protection unit. I'm looking at having a house built and want to make sure to make provisions for such a thing since it's a lot easier to integrate up front. The house would be out in the country with very few trees and long power lines to the property (so lightning-induced power surges would be problematic). (Which is one of the other reasons why I'm looking at EMP protection for stuff in the house. Long power lines are bad in a solar-storm EMP environment.)

Tagged for info.  HD has the Square D HEDPxx boxes with 25Ka, 50KVa and 80Ka versions available from $68 to $153.  https://www.homedepot.com/b/Electrical-Electrical-Cords-Whole-House-Surge-Protectors/Square-D/N-5yc1vZc4nxZal2/Ntk-elasticplus/Ntt-surge%2Bprotection?NCNI-5&sortby=bestmatch&sortorder=none

I use the Leviton 51120-1 whole house surge protector.

Ten years ago that was about the only choice.

Now you can also get the Eaton CHSPT2ULTRA and the Siemens First Surge FS140. Both have higher ratings than the Leviton. Both are more costly.

Any of them will do a fine job if properly installed.

I didn't realize I had one of those already installed. Generator folks were over here the other day doing yearly maintenance, and I asked if they do everything electrical, and then about getting a whole-house surge suppressor. Apparently the ATS already has one on it.

So now everything coming into the house has a surge suppressor on it. Power does, my cable does (both grounded at the service box but also the coax termination at the modem runs through a UPS with suppression), and antennas do.

Great little investment to cover against backfeeds which are a common enough occurrence during power outages.

Surge suppressors don't protect against back feeds.

From an EMP perspective you want to have both entrance protection as well as point of use protection. The entrance protection keeps the big stuff out. The point of use protection absorbs whatever gets coupled directly into your internal house wiring.

In my house every piece of entertainment, computing and radio technology is plugged into at least a small UPS. As a result I lost nothing to a power surge that was so-protected. Same for antenna connections. It was the HDMI and Ethernet protection I was light on.

The Siemens unit is the one Art recommended but couldn't remember the name. Seems like that would be the first line of defense for lightning. I've currently got surge protectors for my computer and radio stuff. I may have to invest in those UPS/surge protectors that are double-conversion on-line types, meaning they take AC from the wall, convert to DC, parallel that with the battery back up, then convert DC back to AC to power the outlets. I've read they can really clean up power for sensitive electronics. I wonder how they are for RF noise if I want to use them for my radio power supplies?

No need to overcomplicate your decision process. I have a total of 8 UPS units in the house, from the cheapest Amazon units to the fanciest rack mount systems. Brands include Amazon Basics, Cyberpower, APC and Minuteman. All work perfectly, none generate RF. The only thing not so protected is the KPA1500 amplifier.

Hadn't thought about what to do with an amp. I don't have one right now but once I get a house with 220 in the "shack", I'll most likely buy one. A whole house surge protector would protect it some, I'd imagine.

I recently attended a commercial HVAC controls class put on by one of the commercial HVAC manufacturers.  After the class we toured the factory including the warranty return shop.  Several of the warranty return pieces they had kept for show and tell were the result of lightning strikes. One of their ugly repeating return stories involved a college campus with centrally controlled building automation with CAT5 between multiple buildings.  Those long runs were picking up the pulses from lightning strikes that weren't even close and frying the com boards on the HVAC network.  In that case it was practical to switch to fiber which resolved the problem.

Completely off topic, another shop at the factory of interest was the control board prototype shop.  Their boards are 4 wafers thick, so there are multiple trace paths, not just the front and back.  Some of the surface mount components were only the size of a speck of pepper.

I watched a strike hit the neighbors property, just happened to be looking out the window.

Though I have not measured it, I estimate the distance to the strike point to be about 75 yards.

Shack is below ground in the basement.

I suffered no ill effects on any equipment, but I keep my shack gear completely isolated from the outside when not in use.

Nothing plugged in to AC system. ( I use a very large power strip that all 120v equipment is plugged into and that power strip is unplugged when not in use ). 240v amp connection unplugged.
Equipment grounds disconnected ( 3rd prong on power cord, see above )
Antennas disconnected. ( self explanatory )
Outside RF ground disconnected. ( through use of a knife switch )
Equipment ground buss has all equipment grounds tied in together but is isolated via a knife switch to the outside grounding system )

It isn't perfect because I just plop the coax on the basement floor. I need to fix that in case of a direct antenna strike and the 600 ohm ladder line does come into the shack but is disconnected from balanced tuner via a big knife switch. So it is possible to get bolt energy into the shack, but no real difference than the bolt coming in via the house AC wires that come into the shack.

@Mach

The real point is that the entire rest of your house got EMP'd by that lightning and it's all still working fine. And none of that stuff has any special protection. Meaning that EMP is not the instant death sentence preppers dream it is.

I'm glad to see the discussion on Dr. Bradley's offerings.  I wasn't trying to troll.  I bought a handful of the PolyPhaser IS-NEMP-C0 units from him about 2-ish years ago for about $125 each IIRC.  Crazy to see him list them at $325 now, jeez.



That's what I have on my house.

I recall some details about the government EMP tests on vehicles.  The testing group had to borrow the vehicles from other agencies, and had to agree to replace any damaged vehicles.  So at lower EMP levels, if a vehicle had any sort of failure, even the most minor, it was pulled from the test, with no exposure to the next higher pulse.  We don't really know what would have happened to those vehicles had they all been subjected to the maximum pulse.  So to say that "the test showed only minor effects" is really not accurate.  Such a test methodology would never survive proper peer review.  Jeffrey Yago has pointed this out in recent years.

The Soviet Project K EMP tests are said to show damage to diesel generators by breaking down their windings, causing later failure (link 1, link 2).

So I concur that the prepper porn novel idea of EMP is way overblown, but I don't think it's conclusive that only long runs of comm and power lines are vulnerable.

I agree.

Neighbors house lost a bunch of stuff from the surge, and had a fire start in the walls.

Nobody was home. Luckily adult son and I saw it happen and ran over because we thought the steam was smoke. saw the driveway blown up and called the fire department.

They found the fire pretty quick with thermal, so luckily we saw it, otherwise the house probably would have had a big fire.

Bolt hie a piece of rebar in the ground on the other side of the driveway. Bolt went into ground, found an irrigation pipe full of water, followed that and the explosive steam blow up the driveway. It got to the end of the pipe and jumped 15 feet up and into a security light above the garage, then went into the wires and started a fire in the garage in the wall.

That convinced me you can try, but there is no guarantee you can divert that bolt, that just jumped a 3000 foot air gap, to go where you want it to go.

It's probably more precise to say that long runs of conductors (comm or power) will cause equipment connected to them to be (more) vulnerable. That includes things exterior to your home as well as interior to it.

Also keep in mind that surge protectors can help prevent damage from nasty power spikes. I saw a lot of those in Puerto Rico because of the damage to the power grid being repaired in a somewhat haphazard fashion. We had one of our teams get their radio power supplies blown out because of one such spike. At the hotel we were billeted at, one evening the power went off-on-off-on about 5 times in quick succession (like 5-6 seconds). That can't be good for electronics.

Definitely isn't. We had a bad windstorm rip through here in March, with wind measured at 70-80MPH steady. This caused a lot of power flickers when it first hit before the power fully went. None of our electronics really suffered as they have surge suppressors, with the exception of a color laser printer. It was indeed on a surge suppressor, but the rapid flickering of power killed the power supply on it. When it started flickering I turned it off to prevent it from happening and it just never turned on again.

What kills power supplies is the sudden charge or discharge from cold. Usually PSUs on computers will die on power-on as the sudden influx snaps something inside. I've only ever had one die during operation.

Hence the 8 UPS's in my house

Plus, I live in the sticks on an unimportant circuit with only 34 subscribers. The power here is not terribly reliable. I don't want my TV entertainment to be interrupted while I wait for the standby generator to kick in

There is a powerline phenomenon that is really good at killing power supplies. Accident, wind, falling tree or something shorts two phases together out of the three phase system... if you're on one or the other phase, the combination of phases doesn't raise the peak voltage, so a surge suppressor does nothing, but it raises the RMS voltage a lot and will toast power supplies.