Cellphone radiofrequency testing by the Chicago Tribune has gone on for over a year, in accordance with the publication. The RF Exposure Lab was selected for the trial, and took one sample from 11 different phones, and positioned them between a sensor and a container of fluid with RF absorption properties the same as human flesh.
Tests were carried out in accordance with what the manufacturers use for a spec as mandated by the US Federal Communications Commission (FCC). Within the case of Apple, that’s 5mm from the surface of the skin. A further check was carried out at 2mm, chosen by the third-party as an average of a pockets fabric thickness.
Samsung tests at 10mm and 15mm. Despite 5mm, 10mm, or 15mm, the FCC requires that at the level of closest exposure, customers cannot take in more than 1.6 watts per kilogram, averaged over one gram of tissue —that is known as the “specific absorption rate” or SAR.
Tests are carried out with a probe immersed in a tissue simulating fluid. A base station simulator is used, with a tester placing a call to the smartphone being examined, with settings on the base station adjusted so that all the things are on the same band, frequency, and channel. The highest radiofrequency radiation is used for the utmost over a spread of tests in the course of the regulatory approval process.
In a worst-case, from 5mm away, the probe embedded within the ersatz tissue obtained 2.64 watts per kilogram throughout the third-party checks with an iPhone 8. An iPhone 7 delivered 2.81 W/kg, and a different iPhone 7 received the same result of 2.50 W/kg.
Motorola instructed the lab that they believed that a proximity sensor hadn’t been properly engaged. When the lab followed Motorola’s instructions, a cellphone which exceeded the SAR restrict thrice, passed the test at 5mm.
Similarly, when an iPhone 8 was grasped, it too was under the limit at 5mm —however, the iPhone 7 was not. When pressed for more information on how the initial testing was carried out, and how the lab could further enhance the testing, Apple would not comment.
Apple took the issue with the testing by the newspaper and issued an announcement saying that the tests have been inaccurate because of the test setup not being as per procedures essential to properly assess the iPhone models.