[K3PZN-List] EMP preparedness, Ben

[Philip Karras]

Ben has opened a good path for having a radio that will survive, anything with tubes in it will.
The problem with EMP is the electromagnetic forces created which induce currents in circuits. Tube when turned off are vacuum insulators, transistors are not, any induce current in a transistor circuit must go somewhere and if they are too large they take out the transistors. Also, due to using ICs and now surface mount ICs and transistors becoming smaller and smaller the induced current needed to pop them is getting smaller and smaller.
Sorry, I do not have the numbers but I'm sure that can be looked up. NSAS has to be doing studies on all electronics they send up as does every satellite manufacturer because if they don't know what their sat can take and what is too much they won't know how to protect the electronics.
Now, as to preparing, I haven't worried about it much for a number of reasons. First, if it is natural we'll have enough notice to take precautions, usually days ahead of time we know if a solar event will affect us.
If it is a man made event, other than having backup radios protected, or ones that use tubes and are normally robust enough to weather this kind of storm, we really can't do much. I do have a backup HF radio in a metal filing cabinet, probably not as safe as it could be but as I said before, if it is a man made event, for it to cause an EMP of sufficient power to destroy our radios we'd have far more to worry about or nothing at all to worry about if that event was close enough to us to affect the radios because, at present, the only known way to man make such an event is with an atomic/nuclear bomb. Though I know that the US military is trying to do it without such a devastating event. But then they wouldn't be what we need to worry about anyway.
Here's a good link and I'll comment a bit on this as well:
https://en.wikipedia.org/wiki/Nuclear_electromagnetic_pulse
"In July 1962, a 1.44 megaton United States nuclear test in space, 400 kilometers (250 mi) above the mid-Pacific Ocean, called the Starfish Prime test, demonstrated to nuclear scientists that the magnitude and effects of a high-altitude nuclear explosion were much larger than had been previously calculated. Starfish Prime made those effects known to the public by causing electrical damage in Hawaii, about 1,445 kilometers (898 mi) away from the detonation point, knocking out about 300 streetlights, setting off numerous burglar alarms and damaging a microwave link.[8]"
and
"The relatively small magnitude of the Starfish Prime EMP in Hawaii (about 5.6 kilovolts/metre) and the relatively small amount of damage (for example, only 1 to 3 percent of streetlights extinguished)[11] led some scientists to believe, in the early days of EMP research, that the problem might not be significant. Newer calculations[10] showed that if the Starfish Prime warhead had been detonated over the northern continental United States, the magnitude of the EMP would have been much larger (22 to 30 kv/m) because of the greater strength of the Earth's magnetic field over the United States, as well as its different orientation at high latitudes. These calculations, combined with the accelerating reliance on EMP-sensitive microelectronics, heightened awareness that EMP could be a significant problem."
In 1962 we did not have all the extremely small transistorized radios & no computers to speak of at all. If they did that today not only would we know but the government might be called to pay us all back for equipment lost. Almost 1500 km Perhaps with one or two of these they could render the US electronically blind & the power grid would be no more hurray for above ground wires!. That probably would not contaminate the earth too much either.
73 de ke3fl,
Phil.ps: I changed the spelling of kilometres to our spelling of kilometers in the article quotes.