Accurately Test Your RF Emissions

Ask any real estate agent about cell towers, and he or she will tell you that they are a real concern to property buyers. Much of the public continues to be nervous about the radiation levels of today’s wireless devices and infrastructure. Regulations exist worldwide to enforce safe emissions levels in wireless equipment. Government agencies and standard-setting organizations carefully detail how to carry out these tests. You also can use spectrum monitoring to effectively test RF emissions, as this equipment moves quickly through the spectrum.

Rapid results are of great benefit in case an issue does arise with emissions levels. Exposure to high levels of RF energy could cause damage to humans, as it can quickly heat tissue. (Think about how your microwave works.) Typically, people encounter levels of RF energy that fall very far below the levels required to do such damage. Since the advent of the cellular industry, however, concern also has focused on these lower levels.

Because the low RF energy levels will not cause heating in the body, they are dubbed “non-thermal.” Research still has not proven that non-thermal effects cause harm. To ensure that RF energy stays within safe limits, government agencies and standards-setting organizations worldwide monitor new findings continuously and adjust regulations if needed.

Emissions must generally be below the provided tables and emission levels at different frequencies. Using spectrum monitoring equipment, you can easily set up limit lines to match these specifications for network equipment. If any site of RF energy exceeds that level, you can set it to send an alarm or other notification. This approach is well suited to checking the signal strength at a location after a new tower begins operating.

With a modern fast Fourier Transform (FFT) analyzer, you get almost the whole spectrum in one snapshot. The alternative is like looking at it through binoculars or a monoscope and only seeing a small piece while sweeping across the spectrum. Time also is a factor. Some labs use older equipment, such as swept technology, which takes a long time to cover the frequency of interest.

For accurate device testing, a shielded anechoic chamber provides superb results. Because these chambers are lined with lead or metal, no RF energy can enter. Very sensitive antennas measure the radiation coming from the product. By altering the product’s position, you can test it at different angles to determine the amount of RF energy being radiated. This approach can easily determine a product’s class (i.e., for industrial only or home/small office use).

While regulations often cite a specific procedure or piece of equipment to make that measurement, that is usually not the only way to perform such measurements. Often, it is a matter of simply updating the documentation. More thorough testing in a shorter time makes this step worthwhile. For those who are unsure, simply ask to see some RF emissions measurements made. When you compare them to the results from the standard equipment, you will find that the new approach successfully made the measurements in less time. Sure, the old ways are tried and true methods that work. But that is not a good reason to avoid testing out new approaches—especially when they perform better in helping to alleviate public concern over negative health effects.

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