Who wants to make his own shielded passport or credit card sleeve? Or line a purse, wallet, cellphone case or backpack? Add a shielding liner to a pocket? Wrap a wifi node to block radiation output? Repair a fencing lame? Shield a part of a circuit board? Make an RF gasket? Shield your homeopathy bottles? Attach a ground cord to a fabric? There are hundreds of uses for this versatile shielding patch. A peel-off paper backing reveals a super strong conductive adhesive that keeps the patch where you put it. Easily cut to any shape with ordinary scissors, this metalized fabric is conductive on both sides, completely flexible with no stretch, and solid black in color. 40-50 dB from 10 MHz to 10 GHz. You get two pieces, each 5.5x8 inches. Not intended to adhere directly to skin. Do not machine wash.
Designed to be “leaky”, it permits only a fraction of the RF radiation to penetrate. Exposure to people is reduced (typically 90-99% reduction), and the device usually still works, but with a more limited range. Great for when you permanently or temporarily want to quiet microwave levels without fully turning off the source. Place it over cellphones, cordless phones, two-way radios, smart devices, even wifi routers. Sturdy metal. The two larger units have convenient handle and access holes for wire and cable pass through. Pick the sizes which meet your needs.
The recent study  about cell phones causing cancer in rats should be taken with a grain of salt when making the connection to humans . In particular, the rats in the study were exposed to radiation power densities of 0, 1.5, 3, or 6 W/kg (see p 7 in ref. 4 below). This would be equivalent of the 100 kg human getting up to 600 Watts — basically getting microwaved. As discussed earlier, cell phones are hundreds of times weaker.
Moving the meter around the case, we detect readings on the side, back and front of the case. We use the multi-directional TES 593 meter which measures 10 MHz to 8GHz. We use the unit of micro-watts per square centimeter, which looks like this little symbol: μW/cm² and we use it on the max setting which shows the maximum measured value. In non-science speak: the highest level of RF we see, which could be from the back the side or the front.
The use of "hands-free" was not recommended by the British Consumers' Association in a statement in November 2000, as they believed that exposure was increased. However, measurements for the (then) UK Department of Trade and Industry and others for the French Agence française de sécurité sanitaire environnementale [fr] showed substantial reductions. In 2005, Professor Lawrie Challis and others said clipping a ferrite bead onto hands-free kits stops the radio waves travelling up the wire and into the head.
Launched at the U.S. Food and Drug Administration’s request 10 years ago, the NTP study dosed rats and mice of both sexes with RF radiation at either 1.5, 3 or 6 watts of radiation per kilogram of body weight, or W/kg. The lowest dose is about the same as the Federal Communications Commission’s limit for public exposure from cell phones, which is 1.6 watts W/kg. The animals were exposed nine hours a day for two years (about the average life span for a rat), and the exposures were cranked up steadily as the animals grew, so the absorbed doses per unit body weight remained constant over time.
The exact source of radiation in a cell phone is from the transmitter, a device located near the antenna that converts audio data into electromagnetic waves. The amount of radiation a cell phone can emit is limited by legal restrictions in the U.S., Canada and Europe. Additionally, the average radiation levels of most mobile phones are available to the public, courtesy of the Federal Communications Commission in the U.S.
*SAR values are from tests conducted by Pong Research Corp on March 29, 2012 and submitted to the FCC on May 31, 2012. Because the SAR values were submitted to the FCC in graph form, EWG estimated numerical SAR values based on the chart available in WT Docket 11-186 (http://apps.fcc.gov/ecfs/document/view?id=7021921006). Pong’s filing to the FCC did not indicate whether SAR measurements were done at the head or in a body-worn configuration. In a personal communication, Pong informed EWG that the SAR measurements were done in a body-worn configuration, with the same distance from the test mannequin used by the phone manufacturer. Tests in the body-worn configuration were done at a 10 millimeter separation distance.
“The evidence so far doesn’t prove that cell phones cause cancer, and we definitely need more and better research,” says Michael Hansen, Ph.D., a senior scientist at Consumer Reports. “But we feel that the research does raise enough questions that taking some common-sense precautions when using your cell phone can make sense.” Specifically, CR recommends these steps:
Perhaps more importantly, what types of radiation are causing, or likely to cause, or are suspected of causing, harm to humans? Is it the “harmonics” from the transmitter? Is it the RF from the circuitry? Is it the primary frequency on which the cell phone operates? This is important to understand. If the problem is the primary frequency on which the cell phone operates then forget the case and ditch the cell phone.
There was also “equivocal” evidence that it raised the risk of heart conditions, and led to evidence of DNA damage. Baby rats born to mothers during the trial had lower birth weights. The scientists also found a statistically significant increase in lymphoma (cancer of the lymph nodes) among female mice and heightened rates of liver cancer in the male mice. All those findings were labeled “equivocal.”
According to the FTC, there is no scientific proof that so-called shields significantly reduce exposure from electromagnetic emissions. Products that block only the earpiece – or another small portion of the phone – are totally ineffective because the entire phone emits electromagnetic waves. Such shields "may interfere with the phone's signal, cause it to draw even more power to communicate with the base station, and possibly emit more radiation." The FTC has enforced false advertising claims against companies that sell such products.
These experimental findings raise new questions as to the potential for radiofrequency radiation to result in cellular changes and offer potential avenues for further laboratory studies. Cancers in the heart are extremely rare in humans, where the primary outcomes of potential concern with respect to radiofrequency radiation exposure from cell phones are tumors in the brain and central nervous system. Schwann cells of the heart in rodents are similar to the kind of cells in humans that give rise to acoustic neuromas (also known as vestibular schwannomas), which some studies have suggested are increased in people who reported the heaviest use of cell phones. The NTP has stated that they will continue to study this exposure in animal models to further advance our understanding of the biological underpinnings of the effects reported above.
Still, despite the odds, these fears could be around for a while — because it’s hard to prove that cellphone radiation doesn’t cause harm. There are just too many combinations of genes, environmental exposures, patterns of cellphone use, plus a healthy helping of random chance to consider. It’s why we’re still having the conversation about whether coffee, for example, is good or bad for us. So while the bulk of evidence points to no health effects from cellphone radiation, the scientific literature is still somewhat mixed, Foster says. “Someone who wants to worry can pick and choose and find a lot of evidence that would support their theories.”
Over time, the number of cell phone calls per day, the length of each call, and the amount of time people use cell phones have increased. Because of changes in cell phone technology and increases in the number of base stations for transmitting wireless signals, the exposure from cell phone use—power output—has changed, mostly lowered, in many regions of the United States (1).