Your post shows you know nothing about EMP.
The kind of EMP that is dangerous over a wide area is produced when the detonation is above the atmosphere. At the altitude you detonate it...there is NOTHING to kill you. It's detonated hundreds of miles above the sfc. Reason: Line of Sight. The higher and stronger the blast...the more distance the EMP travels across the sfc of the earth.
The blasts in the 50's and 60's that you are talking about were sfc detonations. WITHIN the atmosphere. Its the Compton Effect that creates the EMP when gamma radiation hits the upper atmosphere. This didn't happen in those nukes "we set off"...except the ones we set off above the atmosphere.
Educate yourself on EMP. You can still disagree with respect to the damage it will cause...but your post shows you don't understand what is being said.
Of course if there is a sfc blast...we've got bigger problems than EMP. The concern HERE (in this article) is a 1+MT blast 200+ miles above the sfc. That's a completely different animal. If its running (and it has a chip it in...etc)...it will get fried.
And using microwave screens is downright funny.
A microwave and "emp" pulse are two completely different things.
Those screens are simply metal, which reflect the microwave back into the oven. Although the "metal" in microwave doors these days is transparent and built right into the glass, the plastic "screen" is useless.
So rather than srounge around for old, early microwave screens, just use a piece of steel screen to block the evil emp waves, it's do the same thing- which is nothing.
One of the highest was at an altitude of 540 km (335.5 mi) and used to determine the effects of the blast and radiation in the exoatmospheric environment.
The U.S. program began in 1958, with the Teak and Orange shots, both 3.8 megatons. These warheads were initially carried on Redstone rockets. Later tests were delivered by Thor missiles for Operation Dominic I tests, and modified Lockheed X-17 missiles for the Argus tests.
The USSR also did lots of these kind of tests.
EMP devastation produced:
The strong electromagnetic pulse (EMP) that results has several components. In the first few tens of nanoseconds, about a tenth of a percent of the weapon yield appears as powerful gamma rays with energies of one to three mega-electron volts (MeV, a unit of energy). The gamma rays rain down into the atmosphere and collide with air molecules, depositing their energy to produce huge quantities of positive ions and recoil electrons (also known as Compton electrons). The impacts create MeV-energy Compton electrons that then accelerate and spiral along the earth's magnetic field lines. The resulting transient electric fields and currents that arise generate electromagnetic emissions in the radio frequency range of 15 to 250 megahertz (MHz, or one million cycles per second). This high-altitude EMP occurs between 30 and 50 kilometers above the earth's surface. The potential as an anti-satellite weapon became apparent in August 1958 during Hardtack Teak. The EMP observed at the Apia Observatory at Samoa was four times more powerful than any created by solar storms, while in July 1962 the Starfish Prime test damaged electronics in Honolulu and New Zealand (approximately 1,300 kilometers away), fused 300 street lights on Oahu (Hawaii), set off about 100 burglar alarms, and caused the failure of a microwave repeating station on Kauai, which cut off the sturdy telephone system from the other Hawaiian islands [1]. The radius for an effective satellite kill for the various prompt radiations produced by such a nuclear weapon in space was determined to be roughly 80 km. Further testing to this end was carried out, and embodied in a Department of Defense program, Program 437.
There are problems with nuclear weapons carried over to testing and deployment scenarios, however. Because of the very large radius associated with nuclear events, it was nearly impossible to prevent indiscriminate damage to other satellites, including one's own satellites. Starfish Prime produced an artificial radiation belt in space which soon destroyed three satellites (Ariel, TRAAC, and Transit 4B all failed after traversing the radiation belt, while Cosmos V, Injun I and Telstar suffered minor degradation, due to some radiation damage to solar cells, etc. [2]). The radiation dose rate was at least 60 rads/day at four months after Starfish for a well-shielded satellite or manned capsule in a polar circular earth orbit [3], which caused NASA concern with regard to its manned space exploration programs.
So, to cause the kind of emp that would be needed to destroy all electronics, over a specific area would have to be low enough that it would also kill everyone.
Higher detonations would knock out satellites, including their own.