Watchfire of Danville, Illinois of the US has drawn attention to problems seen in some LED displays that have been sold in the US without meeting FCC approval. The company said in a white paper that a chicken restaurant franchise in Texas received a cease and desist order when it caused problems with radio transmissions at a local airport. Watchfire believes that the main problem is a ‘receiver card’ between the data cable and the LED modules. The data is transmitted to the LEDs and it is this architecture that is a problem.
This results in a field of antennas that radiate massive emissions, Watchfire said. Even if the cables are not ribbons and even if they are shielded, they still emit far too much electromagnetic noise to pass FCC guidelines. The firm said that the level was 100 times the FCC guidelines in one test and a complete redesign is often needed.
Analyst Comment
There’s a huge number of LED suppliers in China and not all will meet (or even understand) the testing requirements. There is also a wide range of prices in the market and one way that suppliers will keep their costs low is to reduce testing. As the saying has it, “Caveat emptor” (let the buyer beware!) (BR)
