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The Hidden Secrets Behind the RF Bandit and Low-Cost Products

On a recent visit to China, featuring several factory tours, I learned the product shipped to Europe from three of those factories was built to the EMC standard. Not so for what was being shipped to the U.S.

Imagine a show or worship service is soon to begin, and everything has already been tested. The wireless frequency coordination is all done, the video cameras and LED wall have been set up and dialed in for good IMAG and color reproduction. The sound system also has been tuned, along with the subwoofers having been aligned for maximum impact.

Why risk buying something that is not compliant right out of the box?

The show or service then starts, and as soon as the LED wall lights up, all audio drops from the wireless IEM system, and your artists all of a sudden cannot hear themselves.

What just happened? 

Unfortunately, the wireless was all set up before the rest of the stage was finished, and the frequency coordination was completed prior to all the other gear having been powered on.

What might seem to be a hypothetical situation that rarely happens, though, is actually playing out repeatedly all over the place just to varying degrees.

There is a great collide of issues here, and after several Google searches, there is very little said about the radio frequency, or RF, emissions of LED walls and the pertinent problems that can result. 

Now I know there are lots of LED walls out there, and many of you are probably saying, "but I have yet to have an issue."

Well, if you look back about six years, there were already articles written in Germany about the testing of LED walls. Fast forward to today, and Europe has strong EMC standards while the U.S. has their FCC regulations with Part 15 dealing with intended and unintended radio frequency transmissions.

Now what does EMC mean? With the help of Wikipedia, it provided the following definition:

Electromagnetic compatibility (EMC) is the branch of electrical engineering concerned with the unintentional generation, propagation and reception of electromagnetic energy which may cause unwanted effects such as electromagnetic interference (EMI) or even physical damage in operational equipment. The goal of EMC is the correct operation of different equipment in a common electromagnetic environment.

Basically, the FCC standards in this country say that things like LED walls are not to emit RF noise that would interfere with other equipment, such as wireless mics, Wi-Fi networks, and cellphones.

The reason that matters is during my recent visit to China, which included several factory tours, I had the opportunity to inspect the products they were manufacturing. In addition, I also asked about what gets shipped to the U.S., versus other parts of the world. What I learned was that all the product that was shipped to Europe was built to the EMC standard. Unfortunately, for the product that I saw in three factories probably more than 90 percent of what would soon be bound for the U.S., was not built to EMC, or even FCC, standards.


It all boils down to cost and profit motive. 

There are many certifications that the manufacturer is allowed to use in its effort to "self police," by putting the markings on their products like the CE mark (an abbreviation of the French phrase, "Conformité Européene," which translates to "European Conformity." I could go on for many pages to discuss this further and why I am not happy with the lack of a system that features appropriate checks and balances, but let's hold off going down that rabbit hole.

We all by now know about both the 700mHz and 600mHz frequency band sell off by the FCC. As a result of that auction, all of you reading this have had to replace wireless mics or are on the verge of doing so. 

Now answer me this why are all of you complying with this? Does one think that the FCC is out there en masse driving around with RF scanners, checking that every church on the block is in compliance? Or has there simply been some fear instilled that if you don't comply, you will get in big trouble?

Now let's shift back to LED walls. There are many that are shipped here to the U.S. that don't even have the FCC mark on them. Do you think this should then be deemed a legal electronic device to operate? Or is it like having a 700mHz wireless microphone that you are still using? I can tell you, that if the FCC decides to monitor things like this, it could mean that your $100,000 LED wall will not be able to be used anymore. 

Why risk buying something that is not compliant right out of the box?

A few photos have been attached showing two different LED panels one from THOR: and another was a "factory direct" buy from China. 

Both say they are FCC compliant but the tests show that the THOR: panel is completely quiet of any RF noise and the other panel that "says" it is FCC compliant, but clearly has a whole lot of RF noise emissions with just six panels being set up on that test, amounting to around a 30 dB increase in the RF noise floor on the LED panels that “say” they are FCC compliant, but really are not. (The green line is the RF spectrum with the LED panel turned off, and the yellow is with the LED panel powered on with a white test pattern.)

To sum it all up if you are considering buying LED panels anytime in the near or distant future, recognize that you do get what you pay for. I strongly suggest that you get not only a FCC-compliant product, but one that is also UL listed. There are CE, MET, ETL and UL listings as well, and the UL listing is the most stringent. The UL listing requires that a UL representative actually visits the factory and does inspections related to the product, while the other designations are more lenient. The UL listing is a product safety listing, for the sake of a potential fire or product safety issues, and such a listing points to the product being a wise investment.


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