Electromagnetic Pulse (EMP) of the regional effect scale is a threat during times of potential crisis with a megaton class nuclear equipped foe who also has near-space launch capability for these weapons. An EMP-like event of greater strength and duration is also possible during extreme solar flare events. These types of event are caused by ionospheric excitation of the upper atmosphere by subatomic particles and plasma ejected from a massive solar discharge, this motion in the conductive plasma generates massive amounts of radio waves.
An antenna is any conductor of electricity which inductively converts radio waves into voltage, usually grabbing signals in the microvolt range, but–like a tuned guitar string vibrates in harmony when another tuned guitar string is plucked–an antenna best resonates to a frequency resonant with its length. I would ask the readers to quickly brush up on antenna theory with one of the many excellent tutorials on the Internet.
Fortunately for off the grid equipment like portable electronics and vehicles an antenna that best receives these high energy HF radio waves is measured in tens of meters, unfortunately that makes things like electrical power lines and long antennas particularly well suited to absorbing and transmitting large induced voltages into your sensitive solid state electronics.
It is important to remember, if you are concerned about EMP follow the old instructions for during a thunderstorm, disconnect all antennas and unplug your electronics. At a minimum filter your mains power and install gas discharge tubes on antenna feeds for mission critical radios.
Why do the tube tech gadgets survive where solid state dies from HERF? When an errant voltage spike enters a vacuum tube it can just discharge itself to ground if strong enough (so ground everything electronic at every opportunity), the other large components can also mostly take a sudden flash of high voltage without being destroyed. In solid state the junction size is almost universally quite small and if a reversed voltage is applied against the bias of the semiconductor or an over-voltage is applied the gate is almost always ruined in a way that requires component replacement.
While tube tech is much more survivable in an EMP environment, and HF (shortwave) radios are at high risk being tuned to the most affected bands, I wish to remind the readers that in nearly all other categories tube tech is far less survivable and is notoriously wasteful of precious off-grid electricity. The several downsides to “hollow state” tech is mechanical fragility and short life span compared to solid state, we are talking about blown glass and incandescent filaments essentially like a box of light bulbs to the uninitiated. In a well stocked retreat a tube type radio could be an asset after serious preps have been completed, although for the price of a quality collectors item several high quality military grade (civilian ham radio) solid state radios, the tools and parts to repair them, and proper antenna line and power input traps for errant voltage could be purchased providing much better reliable communications to your retreat than tube tech could.
I actually like to play with hollow state components especially when whipping up simple DIY radios and electronics with the kids, it is a much better visual learning tool which can be used to explain how the solid state components work.
I highly recommend that any serious survivalist invest in several good butane soldering irons, quality fluxed lead alloy solder, and a good tackle box full of replacement components, these can either be harvested from junked electronics or purchased in large grab bags form most large electronics engineering supply outlets. The Brunton Fuel Tool [lighter filling adaptor] makes keeping butane in a usable form easier for a prepper by avoiding the mostly incompatible gas cigarette lighter refill cans and instead using lantern/stove cartridges. These, combined with quality test equipment means that most damaged, shot, soaked, or even EMP-damaged electronics could be saved if you have the time to spare testing out components.
If the readers fail to procure the required hollow state and solid state components and practice their electronics repair skills by kitting or repairing intentionally damaged electronics they will not be able to use these skills during a crisis where mission critical equipment might be taken offline.
You must intelligently train, equip yourself for, and practice your medical, electronics, on and off-road driving, long range bicycling, cooking, fieldcraft, armed and unarmed combat, loaded hiking, carpentry, navigation, boating, food preservation, butchering, cycling, farming, veterinary, water finding, cooking, hunting, fishing, leadership, metal smithing, mechanical repair and fabrication, engineering and other critical survival skills. Being a real survivor has nothing to do with hobby shooting, wide-eyed fanatics, or overweight dude commandos, it is about living your life with the calm confidence that you are walking in the path that the Lord has set out for you while taking reasonable precautions to protect the life you have been given as well as being a vital asset to your family and community. – David in Israel