http://www.futurescience.com/emp/vehicles.html
Magnetos have induction coils, that's sufficient.
Typical E1 pulse component has up to 50KV/m at ground level and is a high-frequency spectrum, you don't need a long antenna for that. EU railway field immunity test is 10 volts per meter and huge portion of industrial electronic equipment fails that already.
Stuff that burns power lines are lower frequency (and lower yield) E2&E3 components.
https://cdn.selinc.com/assets/Literature/Miscellaneous/EMP-T...