Screening: Underground vs. Faraday

Not a clue. But I would suggest having a look at Mil-hdbk-419A. You can fi nd it on the web. It is two volumes on Grounding, Bonding, and Shielding. I am pretty sure it has lots of information on screen rooms, but not sure what it has on below ground facilities. I think it has data on rf attenuat ion by earth at different frequencies.

Dan

Ground is not a great electrical conductor, so it would take some feet of d irt to match a good Faraday cage.

You are probably confusing electromagnetic radiation with ionising radiatio n.

Gamma rays are very short wavelength electromagnetic rays, but the waveleng th is much too short for a conventional Faraday cage to have any effects at all.

Quartz is mainly silicon dioxide. It's not conductive enough to be much goo d as a Faraday shield, and neither silicon nor oxygen has a sufficiently ma ssive nucleus to do anything dramatic in the way of shielding against ionis ing radiation, Natural quartz tends contain even smaller traces of uranium and thorium than granite, so it's a less potent source of ionising radiatio n, which may be a consideration.

Ground conductivity is a miserable conductor compared to a metal Faraday cage. Just shove an ohmmeter into the ground and see for yourself. It doesn't get much better at RF frequencies.

Please note that dirt is primarily an RF absorber while a Faraday cage is an RF reflector.

Location, water table height, pH, salinity, and soil composition.

Bill Sloman answered that. Burying the government is probably for protection again nuclear radiation. Unfortunately, it's currently not possible to bury the entire government.

However, there is Orgonite, which I guess is similar to quartz. The theory is that if you have an RF pollution or electro-smog problem, all you need to do is scatter some Orgonite crystals around the antenna and the harmful radiation is magically absorbed by the crystals. The process is known as "gifting".

I usually lie, but that's ok because nobody listens.

Then I guess the question is how many feet of compacted earth would it take to absorb a certain amount of EMR, in particular interferrence to a buried device from ambient levels of microwaves.

In this regard, I thought there might be some merit in applying a truckload of crushed basalt over the surface since it is paramagnetic.

Orgonite is supposedly based on the research of Wilhelm Reich. The US Government didn't like him much, which is a good recommendation. FDA ordered his books burnt in 1956.

Glen Lewis

The

This'll probably get the spooks onto me. but DRCS were using buried (under soil + concrete) antennas for VLF and thereabouts.

Like I previously mumbled, RF penetration depends heavily on the composition of the dirt and frequency. For example, ground penetrating radar, works quite nicely through several meters of dirt. Sand is best because it's almost RF transparent. The ground penetrating radar frequency of operation covers 40 to 1500 MHz. Close enough to your unspecified microwave frequencies.

I think you'll do better with a truckload of mill slag (iron oxide) or coal (carbon absorbs RF). Extra credit for wrapping everything in welded wire mesh or aluminum foil.

The US government is not particularly thorough at book burning. You can still buy his books:

Very low (below 100 kHz) are often used for cave communication, which would suggest that higher frequencies would be strongly attenuated.

ever hear of ground penetrating radar?

conductivity. dielectric constant, uniformity, magnetic content, depth.

sounds plausable.

It depends rather critically on how wet the ground it is. Dry sand won't have much effect on microwaves, but a wet sea shore will be pretty good. Clean water being inferior to brackish water for this.

Sounds like they might have had a point - pretty much like the crystal healing fraternity and homeopathic medicine. The extent to which it works is entirely dependent on your credulousness and gullibility.

Wow. I never heard of him....

George H.

You can get ELF electric fields to go several miles through 'normal' material. Do a search in oil drilling and 'down hole communications'.

For similar application, I've designed magnetic field based communication systems to go several miles for penetrating those salt layers and sea water. Data rates get a bit slow, though.

• I note that Orgonite "Disarms and repels predatory forms of life". In that case,take a few tons of it and sprinkle liberally on Congress...