Ammo can radio

I have a theory that the protection circuits on the pads of IC's have gotten a lot better since the old days of semiconductors, it would take a lot more of an EMP pulse to fry them than people used to use in their estimates. could be wrong ... I just remember in the 70's, if you didn't take static precautions, you'd fry almost any CMOS chip you touched.
I agree. The chips have much better input protections these days. I design electronics for a living and unlike 20 years ago, I worry very little about ESD. Our production people still have to follow ESD protocols, but I'm quite casual about it at my lab bench. I don't wear an ESD wrist strap and AFAIK I haven't zapped a chip in many many years.

Also, the European CE requirements now require a product to function properly when blasted with radio waves and not be damaged when zapped with a spark gun that simulates a frizzy haired red-head in an wool sweater and nylons scuffing across shag carpet in winter then toughing the product.

I've looked and looked and can't find a definitive article on EMPs vs. electronics, but after a bunch of reading I've formed an opinion. Unplug all cables and if the radio has a metal enclosure it will probably be OK. Stick it in any kind of metal box and it's sure to be OK.

Anything with a cable attached is vulnerable because the cable acts like an antenna bringing the energy inside the enclosure. Most of the energy in "typical" EMPs exists below 50MHz. There isn't an enormous amount of energy above 1gHz. Lower frequencies require longer antennas. At 50MHz an ideal antenna is 5 feet long. At 5Mhz a good antenna is 50' long.

Slots and gaps in a metal storage box to leak radio waves, but not a lot, and only at very high frequencies(because they are small). So long as there's a few points of contact around the lid I doubt enough will get in to damage a radio stored inside. If the EMP is so strong that it gets in and damages the radio, the nuke was so close that you are probably a smoldering pile of ash and beyond caring.
 
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