The spare system is stored in a 33' long aluminum trailer that provides pretty good farady shielding. Should survive all but the most severe EMP event.
Err, pardon my ignorance, but doesn't a Faraday cage need to be iron/steel? I thought an aluminum shell would do nothing at all.
My understanding was that the ferrous metal acts like an antenna, converting most of the electromagnetic wave to electricity in the cage rather than inside the electronic equipment. If properly grounded, the charge would be shunted to ground.
But I'm not an engineer, so I defer to those who know better.