Didn't know where to put this, seems like the most logical place.
Not so much from a HF (have that squared away) perspective but from a breaker panel, auto and generator angle.
I see people selling snap on ferrite cores for incoming house main feeds that snap on the incoming lines, 3 required. They also sell the same for battery cables, along with other means of protection devices for autos, a thing called a trap that plugs into your cig lighters.
They market these things as a "special, or modified" ferrite core with a specific mix, they sell them for $49.00 each. I know things are getting expensive but isn't this a tad high for a snap on?
From what I've been able to research, the core mix needs to be able to stop a few thousand volts (up to 5000) in the 0-300-400mhz range for less than a nano second for the first E1 wave, E2 less voltage/slightly longer, E3 less voltage than E2, could last much longer, minutes or even hours, depending... Naturally, it needs to be of high permeability and not saturate for that short period of time for the E1, the most damaging.
There has to be a less expensive option than what they are selling. Still, I wonder about the effectiveness and also if they are selling these for such a high price out of peoples fear.
I think the most I have ever paid for a ferrite of any type/shape or mix was around $15.00. This lead me to wonder, just what "special" mix they are using and if using these snap on cores to clamp this kind of voltage isn't snake oil at best.
I see EMP's as unknowns orbiting variables and difficult to protect against
Any opinions?