Letter Re: EMP Protection

I have been thinking about EMP damage to circuitry. Am I correct that it only damages computer-chip circuits, or does it also fry transistor type? It won’t harm old type ignition (with points) systems, right? If this is the case, a generator would become just as useless as anything, unless it is stored in a metal cabinet of some kind, right? How air-tight would it have to be to be effective in EMP suppression? (would it need to be totally welded, or just tacked good enough to keep it together? I am a welder, and am thinking about making just such a cabinet for my generator, just for such an eventuality, using old 275 gallon furnace oil tanks for metal, I find they are a good source for fairly heavy gauge metal, long as you ‘burn them’ first, so they won’t cause any problems when ya cut them. So, the old tractors, Harleys, etc. will still run, but everyone else will be walking, right? Can we do anything to protect our existing ignition systems that we use day-to-day? I guess this is more than enough questions for right now. I just found your site last night, and I think you are barking up the right tree. With between 80 and 100 suitcase nukes running around, we are very likely to need this info sooner than later!! “My people perish for the lack of knowledge” is more true now than ever!!

If this is the case, extra ignition systems for these generators would be worth their weight in gold, if not more, if stored properly. Talk about a great barter item!! – S.C.

JWR Replies: To clarify: There is essentially nothing practical that you can do to protect existing vehicle electronic ignition systems or fuel injection systems that are used day-to-day. Just store spares, but they must be shielded. (See below.) The alternative is retrofitting to traditional “points, rotor, and condenser”. This is still possible on many rigs built up until the early 1990s.

Some transistorized circuits are at risk from EMP. Essentially, it all depends on the size of the gaps (gates) between components. The smaller the gaps, the greater the risk. (With advances in miniaturization–now down to 1/10 micron gates on many chips–the vulnerability of microcircuits to EMP has steadily increased. The rule of thumb: the older the circuitry, the better. OBTW, as I’m writing this, I’m looking across my desk at my Zenith Trans-Oceanic multiband (AM/Shortwave) receiver that was built in 1957. It has all vacuum tubes–no transistors. So it is essentially invulnerable to EMP. This radio was just recently acquired for me at a garage sale by my friend Fred the Valmet-Meister. It was priced at just $20 because it had some paint splatters that ruined its collector’s value. Look around and you might find some similar vacuum tube vintage radio bargains.

Your generator itself (the windings and the ignition system–assuming that it has traditional “points, rotor, and condenser” ignition) is not at risk, but its control and switching circuitry probably are at risk. Buy at least one spare set of control parts and store them in an ammo can or other similar “Farady cage.” Putting your whole generator in a metal housing will not work unless you disconnect all external connections–including the power output cables. (Any long metal conductor acts as an ‘antenna” for EMP.) So that is not practical on a day-to-day basis, but potentially viable if you get some warning about international tensions.

Finally, your comment about storing extra ignition systems is spot on! You will need both electronic ignition sets and electronic fuel injection controller sets. Try to find them cheap–perhaps from auto parts shops that go out of business. Concentrate on the most common types for pickup trucks and those ubiquitous minivans. Do some research on commonality between models/model years for each type of ignition set that you acquire, and photocopy that data. (So that they’ll be no guesswork, post facto.) Just be sure to store all of the parts in ammo cans or metal tool boxes. An absolutely tight-fitting lid is not crucial. But if you aren’t certain, wrap items in aluminum foil first, for extra protection.