Radiofrequency Rf Radiation
For example, the EPA chairs an a Radiofrequency Interagency Working Group, which coordinates RF health-related activities among the various federal agencies with health or regulatory responsibilities in this area. Antenna maintenance workers are occasionally required to climb antenna structures for such purposes as painting, repairs, or lamp replacement. Both the EPA and OSHA have reported that in such cases it is possible for a worker to be exposed to high levels of RF energy if work is performed on an active tower or in areas immediately surrounding a radiating antenna.
Mobile phones are often prohibited in hospitals and on airplanes, as the radiofrequency signals may interfere with certain electro-medical devices and navigation systems. Given the large number of mobile phone users, it is important to investigate, understand and monitor any potential public health impact. The electromagnetic fields produced by mobile phones are classified by the International Agency for Research on Cancer as possibly carcinogenic to humans. While both of these studies had strengths, they also had limitations that make it hard to know how they might apply to humans being exposed to RF radiation. A 2019 review of these two studies by the International Commission on Non-Ionizing Radiation Protection determined that the limitations of the studies didn’t allow conclusions to be drawn regarding the ability of RF energy to cause cancer. Because of this, it’s not clear how RF radiation might be able to cause cancer.
The maximum values measured in areas accessible to the public are typically below 0.01 W/m2. Close to the fence of very powerful transmitters, exposure of about 0.3 W/m2 were reported in some cases. The problem with exposure measurements is that, typically, these only encompasses either a short-term measurement of a maximum of 48 hours with personal monitoring, or a spot measurement providing only a snapshot of instantaneous exposure at a single location. In response to public and governmental concern, WHO established the International Electromagnetic Fields Project in 1996 to assess the scientific evidence of possible adverse health effects from electromagnetic fields. WHO will conduct a formal risk assessment of all studied health outcomes from radiofrequency fields exposure by 2016. In addition, and as noted above, the International Agency for Research on Cancer , a WHO specialized agency, has reviewed the carcinogenic potential of radiofrequency fields, as from mobile phones in May 2011.
The tolerance shall be maintained for a temperature variation of −20 degrees C to + 50 degrees C at normal supply voltage, and for variation in the primary voltage from 85% to 115% of the rated supply voltage at a temperature of 20 degrees C. Frequencies shall be paired as shown below, except that channel pairing for channels one through fifteen may be accomplished by pairing any of the fifteen base transmitter frequencies with any of the fifteen handset transmitter frequencies. Perimeter protection systems may operate in the MHz and MHz bands under the provisions of this section. The use of such perimeter protection systems is limited to industrial, business and commercial applications. The antenna type, as used in this paragraph, refers to antennas that have similar in-band and out-of-band radiation patterns. Except as otherwise exempted in paragraph of this section and in § 15.23, all intentional radiators operating under the provisions of this part shall be certified by the Telecommunication Certification Bodies pursuant to the procedures in subpart J of part 2 of this chapter prior to marketing.
There are hundreds of thousands of amateur radio operators (“hams”) worldwide. The Amateur Radio Service provides its members with the opportunity to communicate with persons all over the world and to provide valuable public service functions, such as making communications services available during disasters and emergencies. Like all FCC licensees, amateur radio operators are required to comply with the FCC’s guidelines for safe human exposure to RF fields.
Even near a wireless network station used in homes and offices, the field intensity is typically below 0.5 mW/m2. Another system that is starting to be used in Europe is based on ultra-wide band signals. The frequency range is centred around 500 MHz, applications are wireless microphones, health care applications and traffic control systems. Compliance with the detection threshold for spectrum sensing in § 15.717, although required, is not necessarily sufficient for demonstrating reliable interference avoidance.