Take any portable AM/FM/SW receiver, tune it to a fairly quiet spot on the
AM Broadcast band and pass it near any microprocessor-equipped device,
vacuum flourescent digital display-equipped device or virtually any
consumer electronic battery charger or electronic device with a switching
power supply. Take a walk through the kitchen, laundry room, past the
digital thermostat, the big new TV and both of your computers.
Invariably you will hear a cacophony of noises, buzzes, hums and whistles
that will make your skin crawl.
For the most part, you can thank the folks who design and build the wide
variety of consumer electronic switching power supplies. In the last year I
have found 2 mobility scooters with switching power supplies running their
internal chargers that blot out 7, 10 and 14 MHz nicely. I have found 2
cordless phone battery chargers that put lines on Channel 9 television. At
least 5 larger style battery chargers ( for charging marine batteries and
such) that make great 1-28 MHz QRM generators. Big switching power supplies
for an elevator controller, one satellite dish switching power supply, a
no-name DVD/VHS tape player, several photocells..... the list is endless.
To save pennies and improve the bottom line, RFI suppression parts are
being left out of just about everything sold by big box movers. The RF
pollution is incredible. Enforcement has been non-existent for decades. We
are reaping what we have sown. Moving manufacturing offshore has reduced
cost (and many jobs) but it has also eliminated quality control,
enforcement or implementation of basic design standards that limit RFI and
made those of us who want to use the HF spectrum long for 5 or 10 acres in
the wilderness. The big winners are the folks laughing all the way to the
bank and the folks who make ferrite donuts. ( I just bought 24 2.5 inch
type 31 ferrite cores and it cost me nearly $300! $11.65 each plus
shipping! ! ! )
One of the things that hams must do now is watch very carefully what they
plug in inside their homes. They must develop good working relationships
with neighbors in order to more easily sell the idea that a power cord
wound around a couple of big ferrite donuts will not hurt anything.
It is likely that we will never see a return to RFI-suppressive designs and
enforcement of any standards. Money speaks louder than the minority who are
affected. For RFI snoops like me, it means job security. For all of us who
cherish the HF spectrum, it means a never ending and un-winnable war
against an epidemic that can no longer be stopped. Start looking for your
home in the wilderness if you want peace and quiet.
Frank Haas KB4T
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