during the 50s, 'harden facilities' were built that had 4 foot thick reinforced concrete outer walls to protect 'sensitive and secret military equipment'. guess the facilities worked as it scared the bad guys enough so they didn't launch missiles to test the harden facilities.
to the best of my limited knowledge, the ability to generate a piece of transportable equipment capable of generating an emp pulse of sufficient power to take out sections of cities doesn't exist.
not sure what they are bragging about as most computer centers since the 60's have been build in Faraday cages, put completely on ac/dc/ac power distribution and use appropriate sized filters so to protect ground system, both electrical and signal ground systems.
most forget the signal ground and let it float while some tie the two together thinking they are the same potential.
i chuckled at their example that the last major sunspot activity (1859) took out the advanced electronics at the time - telegraph. duh the bare wires running across the land are super conducting and were not isolated or grounded when they entered the facilities ..