Protecting against EMF bomb

Sure, in metal cans (or under tin-foil hats).

Unplug it if you are worried.

I once worked at a commecial radio transmitter were they concerned about this stuff during the 60's. Many stations even received government funds for this if they happened to operate on the designated 'hardened' frequencies.

The general idea was heavy duty surge arrestors everywhere (similar to lighting arrestors), generous spacing between components, and putting critical electronics in a more-or-less sealed up copper 'Faraday Cages' with surge protection on every incoming and outgoing line. Sometimes entire rooms were lined with copper. Also, lots of stuff was de-rated (i.e. using 1 or 2 watt resistors when 1/4 watt was called for in the circuit design, humongous over-rated power capacitors, etc.).

Every one of these stations had an emergency AM radio with the old CD triangle logo over what were called the Conelrad Frequencies.

My understanding is that electrical equipment that is not "live" at the time of the EMF attack would not be affected. It would be wise to have any necessary batteries disconnected. Burying the items would serve no purpose, other than security.

Not true. Disconnected devices are still sensitive to high EMF fields.

Quite true. Ever put something in a microwave?

Should be (nuclear-)EMP attack?

Buying a car with an ignition coil operated by points (non-electronic) and a vacuum tube radio (and nothing else electronic) would help. Or a bicycle.

-- bud--

The way to protect gear that is not running is to place it inside a sealed metal box (aluminum, copper, ect. The more conductive the better) Note that the lid needs to be REALLY electrically sealed! Usually RF "fingers" or Steel wool "O" rings are used to make contact all around the lid. A simple wire to the lid just won't do it. For small items, [Pack of CDs, DVDs, etc.] new empty paint cans are perfect! Hey for fun put an old useless CD in your microwave! Great way to get rid of your old "secret" files. Microwave might not be too happy with the load, though.

However, any power cord (plus all wires in house and out to power transformer) makes an antenna for the EMP as does any actual antenna. IF the gear is to be operational at the time you must set it up as you would to protect from lightning. Arrestors, grounds etc. Unplugging power cords and antennas helps save gear because it disconnects the "antennas" that pick up the damaging EMI.

"rr" wrote in news:46a8f547$0$4723$ snipped-for-privacy@roadrunner.com:

best way is to have them turned off.

thks, you sounded like you know what you are speaking about.

whats the point of having a hand crank radio for use in emergency, if one of those emergencies might be and EMF event.

this is strickly to store emergency equipment.

Good answer.

Fair comment but the microwave is continuous, whilst the EMF envisaged is transitory. A great deal would depend on the strength of the field and the delicacy of the devices. "a radio, small solar panel, vehicle electonics" are reasonably robust and stand a better than fair chance. I suspect that older technologies (Transistor radios, pre-electronic ignition cars.) would be more likely to survive intact. Wrap it in plastic and keep it somewhere cool and dry!

Just a few general comments on Survival situations:

1) If things really go to the wall, listen out twenty minutes before and twenty minutes after 12 noon. Rationale: A stick in the ground will give you midday and it conserves batteries (And cells!). 2) Listening is good. Transmitting can be risky! 3) Food supplies should be good for three weeks minimum. Looters are shot! After three weeks order should be restored, or you become a survivor. 4) A pump action shotgun could be useful but is debatable. A weapon tends to make you "brave", using it gives your position away and carrying one makes you a threat. On balance NOT carrying a gun makes survival more likely.

The essence of the "mean" in "Greenwich Mean Time" is that it is an averaging process. The Sun is only directly overhead on two days per year (ISTR one of which is 25th of Dec, important to some religionists).

At other times ISTR that the difference between Noon GMT and the Sun being directly overhead can be as much as 40 mins.

Some old-time clocks had an extra dial to show this variation and were known as "Equation Of Time" clocks.

Google on "analemma"

Just how powerfull are these EMP devices? How close do these have to be detonated? It takes a really close stroke of lightning to do damage to electronics. We had lightning strike the electric pole where the transformer feeds our house. The conducted/induced current damaged about half the electrical items in the house from the well pump motor to answering machines. Oddly, the computer and its modem were not harmed. John

Few have witnessed the violence of a 50 Megaton nuclear weapon going off. During the late 1950's, atmospheric tests of this magnitude were common and hence the concerns about an EMP pulse disabling all defenses by blowing out all electronic systems in a wide area. The theory suggests that a high altitude blast would do the most EMP damage and shut the down non-hardened systems in an entire region.

Lighting damage, by contrast is strictly a local event. An indivdual lightining bolt, though violent and potentially dangerous, is made of of comparitively little power, when compared to thermonuclear weapons.

Not very close.

One or two, so the theory goes, can knock out a significant area in the US. The TV series Jericho showed a realistic (again, according to theory) event where one nuke was detonated in the upper atmosphere, knocking out all sorts of gadgets all over the nation.

The Faraday Cage is probably the only thing that can promise protection. Theory again.

The problem with this issue is it's pretty much all theory. We know nukes and other devices can create an EMP that can devastate electronics. We don't know whether it can be done over a significant distance. This would require a fairly large test, which most folks aren't too keen on doing.

For example, will an EMP have an effect on vacuum tube devices? Old, large transistors? What about rebar in buildings, clouds, or other factors not previously considered? Nobody knows for certain.

For small items such as two way radios, AM/FM radios, fancy LED flashlights, and whatever else folks might need, it's best to store them in a solid, metal container that, as other posters have mentioned, are electrically sealed. A military type ammo box would be perfect, protecting the items within from moisture and whatnot as well. Sand down to metal around the seal, then duct tape a thick helping of steel wool around the seam. Won't be pretty, but should survive a good long time.

However, batteries of any type should NOT be stored this way for any length of time. They can leak, destroying your equipment. They also won't hold a charge indefinitely. It would be wise to only store items that can use off-the-shelf batteries, such as AA's, D's, and so forth. You can keep two-way radio batteries around, especially if you have radios that you use on a regular basis. Lithium Ion rechargeable batteries are a bad idea. They almost always have electronic circuits in them to manage charging and use, which would make them vulnerable to EMP damage.

CS

Yes, *VERY* few have witnessed 50MT nuclear weapons doing their thing but far from being common, it was only done once (Tsar Bomba - 58MT), by the USSR, and not in the '50s (October '61). Big nukes were pretty much a thing of fiction.

Interesting but I am not sure of the point you are making. Surely local midday would be indicated by the shortest shadow regardless of whether the sun was directly overhead or not. True there would be a variation depending on your geographic position but in a survival situation I assume most of your interest would be in what is happening locally. I imagine the problem could be overcome by listening out (say) one hour before and one afterward?