Every transmitting antenna emits non-ionizing electromagnetic radiation (NIEMR), also known as radio frequency radiation (RFR). These emissions occur from AM towers, FM and television antennas, cellular telephone facilities, industrial machinery, military equipment and radar installations to name a few. Signals from these antennas are absorbed by the human body and, in sufficient doses and over the entirety of the body, can cause a number of biological effects.
In the United States, the Federal Communications Commission (FCC) governs the levels of RFR to which the public and workers can be exposed not only from single transmitting sources, but also the cumulative contributions of many sources in a multiple use environment (such as an antenna farm or a building roof to which a number of antennas are mounted). The same exposure guidelines have also been adopted by the Occupational Safety and Health Administration (OSHA), through its General Duty Clause.
Smith and Fisher is a leader in providing a full range of services with respect to this issue. We can calculate the predicted levels of RFR from individual antennas. This can be useful in making preliminary determinations as to whether or not a problem area exists on the ground surrounding a tansmitter site, on a tower itself, on a building roof, or in dwellings in the vicinity of a transmitting antenna.
Where multiple antennas exist or where calculated RFR values approach or exceed the FCC’s exposure guidelines, we offer power density measurement surveys. Using the industry’s most advanced meters (a Narda NBM-550 and a Narda SRM-3000), we can conduct surveys of any area to ensure compliance with the Commission’s and OSHA’s human exposure limits for RF radiation. In multiple antenna environments, we have the capability to single out a particular emitter’s contribution to the overall RFR value in a given area, in order to determine if there are instances where that facility may be liable for fines and/or sanctions by the FCC/OSHA for creating or contributing to a hazardous exposure situation for the public or workers that must operate in the affected area.
In situations where excessive RFR levels are measured, Smith and Fisher can provide solutions which will mitigate the problem and reduce or eliminate liability to the owner of the facility and site.
These studies are of value to broadcast station operators (AM, FM and television stations), non-broadcast communications facilities, wireless telecommunications service providers, building owners whose roofs are being used for transmission facilities, military and government applications, and concerned citizens and business owners.
We have conducted dozens of power density studies over the past three decades. These have included complex antenna farms like Mount Wilson (L.A.) and Black Mountain (Las Vegas), the Empire State Building (NYC), and individual homeowners and businesses with RFR concerns. We have also measured power density values on towers in order to develop strategies to protect climbers and antenna installers/maintenance workers from excessive RF exposure from transmitting sources located on the tower.