What is known is that the EMP from Test 184, exploded about 180 miles over the populated area of Kazakhstan as a 1.45 megaton, knocked out a 600-mile underground power line (shielded) that was buried 3 feet underground. It caused fires to the power station that the line was connected to. It also damaged diesel generators. (Most of the details have not been released and/or have remained classified.)
As for the US, In 1962, the US government launched a 1.4 megaton nuclear warhead about 250 miles into the atmosphere over the Pacific Ocean. The pulse results were much stronger than expected. It damaged street lights and microwave links in Hawaii, 900 miles away. The EMP was so intense that it was not accurately measured because “it drove much of the instrumentation off scale”.
And to be sure these were experiments where the detonation was much smaller than the air burst that will be used in a nuclear attack. Hardening is great, but the intent of an EMP is not to destroy, but disrupt the initial efforts by the receiver to protect itself long enough to trap them into being a target where they are.
Besides, after the air burst, a whole bunch of ICBM’s will follow and we will retaliate to the point of making the earth uninhabitable for a few thousand years. I think you call that armageddon. That’s when the cock roaches are supposed to survive and take over. But I doubt it.
rwood
” a whole bunch of ICBM’s will follow and we will retaliate to the point of making the earth uninhabitable for a few thousand years.”
Thousands of years, maybe, but consider Hiroshima today: