Originally Posted by
JonB_in_Glencoe
While I don't have scientific evidence, I have bought several different inexpensive 120volt LED bulbs from different Asian sources on ebay, and every one of those created interference with AM radio (I am a big AM radio fan)...BUT, LED bulbs that I purchased locally, that have a USA brand name like Sylvania, DID NOT create interference with AM radio. It took me a while, But I have replaced all of the Asian RF interference makers. Also, some will produce immediate light when it'd cold, -20ºF...and some LED's are slow to produce light, like the Corkscrew florescent bulbs...Again, the Sylvania produced light when cold. FYI, I am a fan of the Sylvania bulbs.
I suspect they are all made in China, but maybe some American manufacturer contracts specify that FCC rules are followed...Just my guess...