one 20 MT Nuclear bomb at 200 miles up could blanket continental U.S. with effects from EMP

Tactically, a space-based nuclear attack has a lot going for it; the magnetic field of the earth tends to spread out EMP so much that just one 20-MT bomb exploded at an altitude of 200 miles could–in theory–blanket the continental US with the effects of EMP. It’s believed that the electrical surge of the EMP from such an explosion would be strong enough to knock out much of the civilian electrical equipment over the whole country. Certainly this is a lot of “bang for the buck” and it would be foolish to think that a nuclear attack would be launched without taking advantage of the confusion a high-altitude explosion could create. Ditto with its use by terrorists should the technology to get such payloads into space become readily available to smaller countries and groups.  But there’s no need for you to go back to the stone age if a nuclear war occurs. It is possible to avoid much of the EMP damage that could be done to electrical equipment–including the computer that brought this article to you– with just a few simple precautions.
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Protecting Yourself From an EMP

Basically, what we are talking about here is no Iphones, no smartphones, no cell phones, no cell phone towers working, no electrical generators working (I'm not sure what it would do to solar arrays), no generators or electrical motors working and nothing electrical working. So, you would have to order replacements for all these devices from the other side of the planet basically where this thing went off. (Or from non-damaged electrical areas nearby the Blast Area where EMP happened. Also, all hard drives and magnetic memory would be gone and irretrievable unless it were stored in a non-magnetic medium like Cd's or DVD's and the like.