Home-built devices made in quantities of five or less do not generally need FCC authorization. Most commercially-made electronic devices are subject to FCC aut

Home-built devices made in quantities of five or less do not generally need FCC authorization. Most commercially-made electronic devices are subject to FCC authorization regardless of whether they're intended to act as a radio transmitter, because of the possibility of unintended electromagnetic emissions. The local oscillator in a superhet radio receiver, the clock in a digital circuit or the switching frequency of a switched-mode power supply could create harmful interference. The latter is notorious for causing interference today, but TV and radio receivers used to be a significant cause of interference. FM broadcast receivers are subject to verification, which is the lowest tier of authorization and is essentially a self-certification process; the manufacturer must ensure that the product complies with FCC standards, but the testing does not need to be performed by an accredited laboratory. https://www.ecfr.gov/cgi-bin/text-idx?SID=c4285cfe54bf6085bc13a9437ab0957f&mc=true&node=pt47.1.15&rgn=div5 https://www.ecfr.gov/cgi-bin/text-idx?SID=c4285cfe54bf6085bc...