[RFI] AC Line filters- Direct-Drive Washers
w9ac at arrl.net
Fri Apr 4 10:04:20 EDT 2008
For the past year, I have been fighting an issue with my own GE Harmony
direct-drive clothes washer. It's a great clothes washer, complete with
serial I/O port to the dryer and a touch-screen display. Unfortunately,
under 47 CFR 15.103(d) such appliances are still exempt from the specific
technical and certification standards, notwithstanding the general Part 15
requirement that a user of such a device holds no unconditional right to its
use when it causes harmful interference to another service.
I suspect that the last time this section within Part 15 was revised, it
wasn't foreseeable that appliances like clothes washers could hold as much
processing power as a personal computer. The amount of RFI being generated
by this washer is mind-boggling. On 80M, it is producing signals at +50
dB/S9 every 50 kHz or so on my Icom 7800. If this RFI was loosely coupled
to a resonant dipole, I imagine that its effect could be heard to the same
extent as some QRPp transmissions -- it's that strong.
I have tried using some robust AC line filters on the line cord with zero
effect, but I know that I need to dig deep and attack the problem closer to
the source. However, I need to first let the warranty period expire.
I had an opportunity to speak with two of the GE Harmony designers. They
were quite surprised when I found their direct inline-dial numbers on the
Internet. In fact, one of the engineers was responsible for the entire
digital interface. The first words uttered, were "look, we're exempt from
certification with that product." No further assistance was provided and
of course, this was the first complaint he had heard relating to the
Anyone have any similar experiences with the new direct-drive washers and if
so, what specific remedy was used to mitigate RFI? I am completely familiar
with the general concepts of RFI/EMI abatement, but I am looking for
case-specific solutions with actual experiences with direct-drive washers.
More information about the RFI