[AMRadio] FCC Non-cooperation (was ILLEGAL STUFF ON E BAY)
Robert Nickels
ranickel at comcast.net
Wed Mar 17 12:35:43 EDT 2010
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
More information about the AMRadio
mailing list