First, you must have a proper meter. To check for magnetic field emissions, an AC Gaussmeter will work. Most AC gaussmeters will have an internal probe. Simply position the gaussmeter on the phone. Note carefully where the meter is positioned. Make a call and watch the readings. Notice the highest and lowest readings, and make a mental note of the "average" reading. Now, insert the magnetic shield, and repeat.
The tricky part about measuring the radiation from a cell phone is that the emission strength varies widely over time. There will be strong bursts of varying intensity, followed by quiet periods. This makes it hard to compare "apples to apples". Also, because you are measuring up close to the source, you must use a near field meter AND you must maintain the position of the meter very precisely.

“It’s quite informative that the NTP data found evidence of an increased tumor risk in the male rats for glial cells and in the [heart] Schwann cells,” said Joel Moskowitz, director of the Center for Family and Community Health at the Berkeley School of Public Health (who writes about electromagnetic radiation here). “That’s compelling evidence that what we’re seeing in humans — even though the signal is not clear — is highly suggestive, and that there is indeed something real going on with regard to tumor risk in humans.”
That’s why the International EMF Scientist Appeal and a number of health and safety organizations, including the American Academy of Pediatrics and the Environmental Health Trust, have called on the government to reassess the safe levels of exposure to cellphones and other wireless technology and then develop new consumer safety guidelines based on those assessments, Moskowitz said.
Another part of the INTERPHONE study compared more than 1,000 people with acoustic neuromas to more than 2,000 people without tumors, who served as matched controls. As with gliomas and meningiomas, there was no overall link between cell phone use and acoustic neuromas. There was again a suggestion of a possible increased risk in the 10% of people who used their cell phones the most, but this was hard to interpret because some people reported implausibly high cell phone use, as well as other issues.
As our video points out: Measurements will vary with signal strength and other factors and that includes ambient energy. I talk about ambient energy in a lot of my videos-it's the energy that's in whatever environment I happen to be measuring in that's coming from a source of wireless energy that isn't the subject of what I'm measuring.  My home is not a lab of course, but fortunately it's always measured very low for RF radiation. 
Scientists have reported adverse health effects of using mobile phones including changes in brain activity, reaction times, and sleep patterns. More studies are underway to try to confirm these findings. When mobile phones are used very close to some medical devices (including pacemakers, implantable defibrillators, and certain hearing aids) there is the possibility of causing interference with their operation. There is also the potential of interference between mobile phones signals and aircraft electronics. Some countries have licensed mobile phone use on aircraft during flight using systems that control the phone output power.
Please research info supplied by Dr Patrick Flanagan on the One Radio Show last November? He said during the interview that Ferric Oxide Crystals have the same earth Schumann Resonance and can be easily and cheaply bought as Jewellers Rouge. You can simply add some to clear nail varnish and dot all your electricals with it. To neutralise a Smart Meter you should paint the wall in between. I know it works and within a few days of doing this plus painting stones and throwing them (gifting) in close prox of mobile masts black helicopters started harassing me!

Forward your cell phone to landlines whenever you are at home, then power off the cell phone without missing a call. Biological effects can be related to both strength of cell phone radiation dose and duration of exposure, so consider whether or not your communication is urgent. Remember: Use a corded home landline (not a home cordless phone, because cordless phones use electromagnetic microwave technology just like cell phones). Most cordless phone base stations constantly emit microwave radiation regardless whether or not any connected handset is in use. The cordless phone handsets also emit microwave radiation. Corded landlines have no radiation emissions and are the best choice.

Protect your brain from RF (radio-frequency) pollution with this handsome baseball style hat. Specially designed to shield the head from frequencies from below AM through microwave, including cellular phone frequencies. Lined with sophisticated Staticot fabric woven from ployester/cotton with an ultrathin stainless steel fibers excellent radiation protection. This gives this unique fabric a truly comfortable, natural feel and the durability and washability of cotton, but with exceptional reflective characteristics.

And even with these unusually high levels of exposure, the links to cancer were still “mostly equivocal, or ambiguous,” according to the FDA’s statement. In fact, the rats exposed to cell phone radiation actually appeared to live longer than the ones that weren’t, a finding that the FDA’s Shuren says the agency is assessing. The difference could simply be the result of chance, STAT News reports.
According to the WHO, the "precautionary principle" is "a risk management policy applied in circumstances with a high degree of scientific uncertainty, reflecting the need to take action for a potentially serious risk without awaiting the results of scientific research." Other less stringent recommended approaches are prudent avoidance principle and as low as reasonably practicable. Although all of these are problematic in application, due to the widespread use and economic importance of wireless telecommunication systems in modern civilization, there is an increased popularity of such measures in the general public, though also evidence that such approaches may increase concern.[35] They involve recommendations such as the minimization of cellphone usage, the limitation of use by at-risk population (such as children), the adoption of cellphones and microcells with as low as reasonably practicable levels of radiation, the wider use of hands-free and earphone technologies such as Bluetooth headsets, the adoption of maximal standards of exposure, RF field intensity and distance of base stations antennas from human habitations, and so forth.[citation needed] Overall, public information remains a challenge as various health consequences are evoked in the literature and by the media, putting populations under chronic exposure to potentially worrying information.[36]
At high power levels, RF waves can heat up water molecules (which is how microwave ovens work). Scientists used to focus their concerns on the possibility that such heating of human tissue, which is mostly water, might damage cells. In fact, the FCC’s test of cell-phone emissions—which was set in 1996 and which all phones must pass before being allowed on the market—is based on that effect.
Generally speaking, the near-field refers to the RF field close to the antenna and the far-field is the RF field further away from the antenna. Often times when you use your cell phone, your body is often located in the near-field (one wavelength or less) of the cell phone antenna. It is especially concerning when you hold your phone next to your head or wear it on your body as you can be exposed to very intense near-field radiation from the phone.
Most of the research is attributed to "SPSU," which is presumably St. Petersburg State Polytechnic University, and some of the research, it is suggested, was conducted at the Kirov Military Medical Academy, though it's unclear why a military academy would conduct clinical research on civilian cell phone radiation. The names of the scientists who conducted these studies are conspicuously absent, as are any published results.
Finally, Brawley reminded me that cellphones kill humans in another way that we’re already certain about: because of inattention through distracted driving. In the US alone, there were 3,157 fatal crashes in 2016 that involved distracted driving, 14 percent of which included cellphone use, according to the latest data from the National Highway Traffic Safety Administration. That’s not the focus of this piece, but perhaps state and federal regulators could follow places like Washington state, California, New York, and Nevada and heavily crack down on distracted driving with bans or stricter laws.
So you are careful about NOT putting your radiation emitting mobile near your head. That’s good. But think about this: what body parts get the radiation when you put the thing on your pocket, bra, hat, purse, holster or elsewhere on your body? Now your vital and sometimes private organs are basically in contact with the source of the microwaves, getting the largest dose possible. Pocket Sticker is a high performance shielding patch that you stick onto your clothing which reflects that radiation away from your body.
Think of it as a luxurious pillow case for your phone. Soft and attractive, it protects your phone like an ordinary phone case, PLUS innovative near field shielding material built-in to one side shields your body while carrying the phone and shields your head while making calls. BlocSock™ has two compartments, the main compartment covers the whole phone for transport. During calls, put the phone in the smaller “kangaroo style” pouch.

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.

A large prospective (forward-looking) study of nearly 800,000 women in the UK examined the risk of developing brain tumors over a 7-year period in relation to self-reported cell phone use at the start of the study. This study found no link between cell phone use and brain tumors overall or several common brain tumor subtypes, but it did find a possible link between long-term cell phone use and acoustic neuromas.
Manufacturers conduct government-required certification tests using a bare phone, set to transmit at maximum power, with no accessories. The recorded maximum SAR is reported to the FCC and listed in the phone’s manual. A phone tested with accessories under the same conditions can produce a higher SAR because the materials surrounding the antenna can affect the amount of radiation that reaches and is absorbed by the user’s body. A case can influence both the overall amount of emitted radiation and how it is directed.
An analysis of data from all 13 countries participating in the Interphone study reported a statistically significant association between intracranial distribution of tumors within the brain and self-reported location of the phone (7). However, the authors of this study noted that it is not possible to draw firm conclusions about cause and effect based on their findings.