On Mon, 7 Sep 2009 08:21:14 -0400, Paul Christensen wrote:
>I've also given consideration to the filing of a Petition for Rulemaking
>with the FCC to amend Part 15 to include "appliances" that are currently
>exempt from meeting RFI standards. But that kind of filing needs the
>backing of interested organizations. The EU nations have been more
>proactive on this front and my understanding is that their household
>appliances must meet the same strict RFI/EMI standards as is required of
>other electronic equipment.
>This is an area ripe for organizations like the ARRL, NAB, SBE, AES, and the
>like to join forces. It's interesting to note that in the most recent
>edition of RadioWorld, a well-read broadcast engineering publication, the
>front page story addressed the gradual increase in average noise floor over
>time from unintentional radiators. The point the author was making, is that
>the rise in noise floor due to these devices is already having a devastating
>impact on analog AM and HD radio services in North America. What the author
>did not address is the fact that the rise in noise floor is due in large
>part to exempt appliances that internally use computers, inverters, and
>switch-mode power supplies in everything from the clothes washer to the
>toaster. These internal devises by themselves must meet technical
>standards, but as soon as that device is thrown into an "appliance," it is
>then exempt from meeting unintentional radiator standards. Why?
Lobbying by business! Money talks. And a philisophy that government is too
big. And the ARRL was asleep at the switch.
BTW -- another component of increased noise on the AM broadcast band is IBOC
-- In Band On Channel digital broadcasting -- which greatly broadens a
station's sidebands and interferes with adjacent channels.
>We really need to get Part 15 current with the times. As more consumers
>replace their household appliances with models that incorporate RFI/EMI
>emitting technology, the problem will only become worse.
I strongly agree on all counts. The interest groups you mention have been
asleep at the switch on this issue, obsessing over BPL as if it's the only
threat. From direct personal experience, I can tell you that a single
switching power supply sold and installed as a "transformer" for low voltage
lighting, or the rechager for a portable drill can wipe out the entire MF and
HF spectrum just as effectively as BPL. These are only two of many nasty
noise generators, and they are becoming increasingly dominant in their
individual markets. If you don't believe me, visit any store that sells
lighting and look for a "line voltage" fixture that doesn't have a built-in
"transformer" (switching power supply). Or visit a store that sells power
tools -- at least half the models on display run on batteries.
73,
Jim Brown K9YC
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