EMP proof?

[pistolclass]

OK a buddy of mine was saying he thinks these Chinese bikes are EMP proof. There is no computers or hei so is he correct?

[Jay In Milpitas]

Any electronic/solid state ignition system is not EMP resistant unless it is shielded for that.


After the zombie thermonuclear apocalypse only some military vehicles and points ignition engines will be in service. Well, steam too.

[pistolclass]

So my 1971 vette will still be kicking? What is the ignition on the hawk?

[humanbeing]

OK a buddy of mine was saying he thinks these Chinese bikes are EMP proof. There is no computers or hei so is he correct?
There's chip & other s**t inside CDI ...

[Torgo]

Now this is my type of CB question. To answer your question - no, he's not correct.

Imagine your bike getting blasted by a big magnetic field. One of Maxwell's equations basically says that a change in the magnetic field will generate a change in current. So depending on what is exposed, the angle things get hit, and how hard, all the electronics potentially get a surge of current. Pretty much anything connected to an exposed wire will have some EM energy coupled into it with the potential to be damaged.

Now another one of Maxwell's equations says that EM can't go through metal - since the surface electrons move with the field. That's why wrapping things in Aluminum is so popular with some folks.

I did take some RF and EM classes back in the day. It was the end of the cold war, and I had one ex-hippie professor who was quite concerned about this. I do remember him giving us some related homework problems.

[pistolclass]

so this leads to my next question..... how do I emp proof a CB?

[Torgo]

I should clarify this - my background in this area is FCC emission certification and designing for static discharges in integrated circuits, not hardening equipment to survive EMPs. Some of the theory is the same, but take this with a grain of salt. EMPs and solar mass ejections produce levels of EM fields orders of magnitude larger than anything I've ever had to worry about.

The easiest thing in theory would be to store it in a metal box - it would have to be entirely enclosed. Any currents generated would flow over the box, your motorcycle would be unaffected.

If you're out with it, and the EMP comes along - that's a much bigger problem. The frame of the bike is your GND reference, but it's really just a big hunk of metal. So if a magnetic pulse hits, currents can start flowing all over the place. So what may have been your 12V rail and GND, well, that means nothing now.

Hardened components or mil spec stuff, cost a lot more for a reason. They have tolerance levels way above industrial or commercial grade stuff. They may just have more iron/copper to handle more current or add shielding. They may add diodes, chokes, relays, etc to clamp or disconnect circuits when transients hit. They add a bunch of redundancy - you may lose one CDI for example, but you have a switch for the backup. That kind of stuff.

I'm challenged enough just jacking up the bike to tighten the chain, so I wouldn't know where to start on anything like this. Truthfully, if you're really worried about it - buy a spare and store it wrapped up in a bunch of aluminum foil. I bet you that's going to be your best cost option in the long run.

[Jay In Milpitas]

so this leads to my next question..... how do I emp proof a CB?

Natural or man-made EMP?

Natural source is not very likely to damage your CB unless you are many miles up in altitude. Our magnetosphere and atmosphere protect a lot.

If it's man made and you are close enough to the source for it to damage the machine, you have other (much bigger) hazards.

[pistolclass]

My reason for the question is mainly academic. It was more out of a buddy thinking because it did not have hei it would be protected from emps. So is the tin foil hat I'm wear a waste too? ;)