Not to detract from Steve's point, because I agree that RFI from unintentional radiators is a major problem for hams, especially those who enjoy full-range AM audio on HF. But it's important to understand how the FCC approaches the wide range of Part 15 issues - here are a couple of good resources:
FCC: http://www.fcc.gov/oet/ea/procedures.html#sec1 ARRL: http://www.arrl.org/tis/info/part15.html#Myths An A2LA-certified RF test lab: www.radiomet.com/documents/FCC_Guide.pdf Once you're familiar with the terminology used to characterize unlicensed devices, I think most will agree that our problems stem primarily from both Class A (intended for commercial, industrial, and business use) and B (residential) Unintentional Radiators. This can involve both Conducted (interference that is carried along power lines and other conductors to other devices, i.e. our receivers) and Radiated emissions (what Steve measured with his spectrum analyzer). The vast majority of such devices are subject to Verification, which is the lowest level of compliance. Manufacturers are on the "honor system" to do the appropriate testing and label the product accordingly. Even when manufacturers make a good faith effort to comply with Part 15 Verification requirements, the real world implementation may not reflect what was seen in the laboratory. Take for example the noisy LED traffic light that Steve posted about some time ago. Suppose the manufacturer recommended that shielded cable be used between the switchmode controller and the lights to mitigate radiated RFI, but the installers just re-used the unshielded wires that were used for the old incandescent systems. Instant antenna! As hams, we know the length of the wires and whether they're run inside a metal pole or along the side of a wooden one will make a big difference also. Just a made-up example to show that the problem may often not be as simple as going back on the manufacturer of one of the devices in question. Still, the intent of Part 15 is to protect licensed users from interference from unlicensed devices, and the best option we have to enforce current regulations (or potentially get better ones) is to continue to elevate our concerns to the FCC and those who oversee the agency. 73, Bob W9RAN ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/[email protected]/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: [email protected] To unsubscribe, send an email to [email protected] with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
