Long ago, it was fairly standard to provide lightning protection for outdoor radio antennas by installing a large double-throw knife switch -- antenna leads to the center, radio on one side, ground on the other. Double pole for a two-wire feed, single for a plain long wire for a receiver.
This, installed outdoors with suitable thermal protection between the switch/wires and house structure, seems like it ought to still be a good method, and one that's in reach of the cash-strapped starting amateur or SWL. Just step outside and throw the switch before operating and after shutting down, and your antenna becomes a grounded wire (I've read fairly recent research that suggests lightning rods actually repel lightning by grounding off charge build-up on high points of the protected structure; this would work the same way).
Now, heavy knife switches are less visible than they used to be, but they're still around -- look inside any industrial high-voltage or -current shutoff box, and you'll find a knife switch with copper bus bars as thick as a heavy chef's knife and as wide as your thumbnail; on three-phase, it'll be three pole.
Further, knife switches are well within the capability of a hobbyist to build, though heavy gauge copper sheet and bar isn't as easy to find as it once was (and costs plenty) -- one could source all the needed materials in the plumbing section of the local Big Box home improvement store (copper pipe can be flattened to make bus bars and contact clips).
Clearly, there's something missing from my picture of this kind of lightning protection, for it to have been replaced with (potentially sketchy and impossible to genuinely test at the consumer level) gas discharge systems and similar high voltage switching.
Are knife switches to alternately connect my antenna to the radio or to ground obsolete for good electrical or safety reasons, or have they just fallen victim to profit motive on the part of equipment makers and sellers?
