Tom wrote again: > > >Tom wrote: > > and Mike Carrel replied > > > > > > >> I did a remodeling project on what once was a medical clinic. When we > >> cut into the walls, there were sheets of lead in them. > > > >Lead would be used to stop Xrays, nothing more. > > It was a thin layer of lead, would such a layer stop short X rays too?
In general the shorter the wavelength, the greater the penetrating power. Cosmic rays go through everything. Electromagneitc radiation is a continuous spectrum from radio to cosmic rays. Attenuation is a matter of thickness and specific properties; light will travel through miles of fiber optics, but be stopped by a sheet of aluminum. > > > > >> I am interested in stopping EMF, in particular short wave X rays and > >> possibly shorter wave EMF. > > > >Check your numbers. The only thing shorter than Xrays are gamma rays emitted > >by radioactive substances and accelerators. > > I've seen a chart like that, I'll have to visit the library and look at one. Try Google. Ask the right questions, and it is al there for you. > > > > > If I put it into a grounded metal, or > > > >As a first rule of thumb, YES. But EM radiation will leak out of a box like > >water or a gas weakly. There is a whole discipline that goes under the code > >name TEMPEST > > Thanks for that name. Tempest is an unclassified name referring to a classified subject. One does not advertise capability in reading radiation signatures. > > > >What if I > >> had electrical conductors, coming out of the Faraday Cage, would the > >> short wave EMF be conducted with them? Would a transformer stop them? > > > >You bet. They are antennas, as are any gaps in the shielding of the box. > >Transformers only stop DC and can be transparent to everything else. > > Is there some way to make a transformer that is opaque to them? The conventional way is to shiield the primary and secondary separately, and introduce a grounded electrostatic shield between the two, so there is only magnetic coupling. The whole puyrpose of transformers is to trasmit alternating current. If you want to suppress certain frequencies or frequency ranges, you use a filter designed for that purpose, but these do not produce total suppression. > > > > > >> There was a man who was interviewed on C to C AM last week. He talked > > > about cell phones. > > > >The man is misguided. A cell phone when on and in stanby will listen to the > >nearest cell phoone tower, comparing its address with the last address > >received. When you turn it on, it will transmit a burst, reporting in, so > >the system knows where your phone is. Your phone then goes passive, just > >listening until you take it to another tower's cell; it will transmit > >another burst, reporting in, etc. Think logically. Your phone will not waste > >battery power transmitting all the time, nor do the towers want hundreds of > >phones all yacking at it needlessly. > > You don't seem to be concerned about these occasional bursts of > radiation, Mike, he disagrees with you I think him misguided. I turn the phone on, and the burst might last milliseconds. It will listen only until I take it to another cell area, where it might emit another millisecond burst. It probably won't be near my head. If I am talking, then it is transmitting continuously. One must distinguish between the passive mode and active transmission. There one may have a concern. I just had a long conversation with a man who is extremely knowledgeable; he was using a cell phone, and at the beginning of the conversation said he was putting it into speakerphone mode so he would not be holding it against his head. This supports the position of the man you are referring to. > > > > >>Then there are the towers, he said that > >> you don't want to be within 500 feet of one. > > > >Utter nonsense. The individual transmitters have a power of about 7.5 watts, > >equal to a christmas tree light bulb. The are up high so they can be 'seen' > >froma distance and the antennas are designed to emit most of their energy as > >a narrow horizontal fan so as to reach as far as possible. Nearby at ground > >level you get only the feeble leakage from the antennas. They are so safe > >that the FCC does not require site surveys or licensing in setting up cell > >towers. > > Hum, again the two of you are at variance over this matter. He claims > that the side of your head will feel hot from continued cell phone > use. IMHO, this not a good sign. He says that the number of brain > cancers in the vicinity of the antenna continues to increase. RF radiation will produce heating. While a cell phone is a weak transmitter, I cannot say that someone will not feet some warmth. I do not notice it when I use a cell phone. As far as cancers near antennas, he should cite statistics, not generalities. People have looked at this stuff carefully.Truly random events can include clusters of events, so if you look selectively enough you can find clusters of cancers associated with anything. I find it very difficult to believe that the equivalent of a christmas tree light 40 feet in the air and two blocks away is going to produce any adverse biological effects. > > > > >I used the ear jack when > >> I made phone calls, but apparently the EMF follows the wires into the > >> ear jack. If his story is correct, over population will not be a > >> problem for much longer. > > > >His story is not correct, it is grossly exaggerated and misleading. There > >are some allegations that holding a cell phone to your ear places the > >antenna next to your brain and its radiation may affect brain tissue. Years > >ago there was a suit by a man (or his widow) alleging that the cell phone > >initiated a brain cancer at that spot. If this were generally true, there > >would be a worldwide epidemic of brain cancer by now. > > He says that the aforementioned epidemic is here, or rather that we > are just seeing the tip of the iceberg. Scare stories get attention. > > >Think logically. > >People may choose to go hands-free, with a ear bud, and tiny microphone pod, > >and the cell phone in their pocket, and walk around talking to the air. The > >cell phone antenna can then irradiate your leg instead of your brain. > > Hum, good point. > > > > >With the above caveats, long term use of a transmitter next to your head is > >probably not a great idea, but any bad effects are very hard to quantify. > >There were similar concerns about living near high voltage transmission > >lines. There were some stories about clusters of disease, including cancers, > >near high voltage lines. The clusters were there, but evidence linking them > >to the high voltage fields and not some other environmental cause was > >lacking. > > As I understand it, children living in the first house down from the > transformer are at a higher risk than children in subsequent houses. > Adults are at a lower risk than children, and fetuses at a higher > risk. You said transformer, not high voltage line. Utility power transformers have used toixic oils for insulation for years. I believe one of the common ones has been identified as a carcinogen. Conceivably, some leakage of the oil could create a toxic plume around it. The culprit is the oil, not the high voltage line itself. > > > > >Some years ago, Verizon wnated to erect a cell tower at the local police > >station. I attended some of the meetings. A woman was all distressed about > >irradiation of her house because she had read one of the idiot books. She > >was oblivious to the antenna of a 50 kW AM radio station a mile or so away, > >which has houses all around it for decades. Its signal is so strong I had to > >put filters on the telephone lines and my computer modem to avoid > >inteference. I get 25 mV of that transmitter on any stub of wire in the > >house. > > I think that he would say apples and oranges. The wave length of the > cell phone EMF is way shorter than the AM radio waves. > Yes, quite so. But the tower is just a tall stick with a crown of a dozen or so cell phone anennas beaming to the horizon. I live about a block from that tower and enjoy good cell phone performance from the feeble spill radiation of the antennas. Mike Carrell. > > >
