Over the past 30 years, a phenomenal increase in wireless products has occurred. All wireless products use Radio Frequency (RF) energy to transmit information.
Background:
Radio Frequency (RF) energy provides a means to transmit information in a wireless form. This same RF energy, at high enough concentrations, can possibly induce health related effects in body tissue. In an effort to minimize the effects of RF energy upon the general public, the FCC has set forth guidelines for safe levels of RF exposure.
Two levels of RF exposure are defined:
1) General Public (uncontrolled exposure). Applies to human exposure to RF energy in which persons are not fully aware of the level of their exposure and cannot exercise control over the amount of exposure.
2) Occupational (controlled exposure). Applies to human exposure to RF energy as a consequence of their employment and in which those persons exposed are fully aware of the potential exposure and can exercise control over the amount of exposure.
FCC OET Bulletin 65 defines the maximum amount of RF energy that the General Public or Occupational workers may be exposed to. In addition, this bulletin provides acceptable methods for determining RF levels in a broad range of situations. OET 65 offers guidelines for installation practices to assure compliance with the new RF exposure rules.
Your FCC license and your responsibilities:
As an FCC licensee, you must be aware of RF exposure issues and make sure your system is compliant with the OET 65 guidelines.
How to begin:
1) Determine the MPE (maximum permissible exposure) level of the base station or repeater antennas you operate within your two-way radio system. This is a mathematical calculation of the RF signal strength of your radio system. From your MPE, you can determine the RF levels from your antenna at any given distance.
2) Determine if your calculated MPE is above or below the guidelines set forth by OET 65. If your MPE level is below the guidelines chart, you are compliant and no further action need be taken.
3) If your MPE level is found to be above the guideline levels for either General Public or Occupational exposure, then corrective actions must be taken. Some examples of corrective actions are: fencing the tower area to keep the general public further away from the antennas, locking doors on roofs to eliminate unauthorized persons access to an area near antennas, training workers who may work near roof mounted antennas about safe distances to keep from antennas, disabling the repeater when workers must be near antennas, and limiting the amount of time workers may be near the antennas.
Each two-way radio base station or repeater will have a unique location, transmitter power, cable length and antenna personality. An accurate MPE level must be determined from your exact set of circumstances. From your exact circumstances, you will be in the best position to determine what corrective actions, if any, need be taken.
A wide range of normal two-way radio systems will easily be compliant with the new OET 65 guidelines. A few here and there may not be. The FCC is requiring that all FCC licensees determine that they are in compliance with the new RF safety guidelines. Let us assist you !
MIDCOM Service can help you determine where you stand with compliance issues.
We are familiar with the OET 65 guidelines in regard to two-way radio systems. MIDCOM Service can provide an exact MPE calculation for your system. From there, we can work together to determine what level of corrective actions, if any, you should implement for your two-way radio system.
Remember, the OET 65 MPE exposure guidelines generally apply to fixed mounted base station / repeater antennas for typical two-way radio systems. Two-way radio mobile (vehicle) radios, portable radios and Cell phones are governed by a different set of FCC guidelines and must pass these tests before they can become FCC certified for sale in the United States.
Recommended reading is the FCC/LSGAC RF exposure guidelines. LSGAC and the FCC have developed this guide to aid local governmental officials and management personnel in understanding safety issues related to radiofrequency emissions. PDF format.
Links to more information
FCC FAQ Frequently Asked Questions on RF Safety from the FCC
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RF Exposure and Safety
