[EMAIL PROTECTED] quotes and writes:
>
> In a message dated 7/21/01 7:57:23 PM, [EMAIL PROTECTED] writes:
>
> <<
> My problem is definitely worse in the evenings too. I've suspected
> something to do with lights. Have you tried turning on all the same lights
> during the day? Also I've wondered about the television (also on cable); it
> tends to be operating at night more frequently than during the day. (I've
> not tested this theory, though.)
>>>
>
> I wish I had known you had dimmers before, Mary.
>
> I'd suspect the dimmer(s) for the following reasons ...
>
> The dimmers operate by "chopping" the alternating current waveform in such a
> way that very high frequency harmonics are generated.
>
> Those harmonics may be so very high in frequency that they can pass right
> through the RFI (radio frequency interference) filter in your monitor.
Just questions to explore other than the sometimes difficult business of
eliminating possible causes of interference by physical moves and turn-offs.
I'm not a EE, but perhaps a couple of you who are could comment on the
possibly of using some detection equipment. Any use for a simple AM/FM
portable radio on battery power and set to AM reception? I know that mine
will pick up 60 Hz buzz from dimmer switches, monitors, and TV's even when
"turned off." What do these emanations mean for the problems folks are
having? Do electronic supply stores which cater to labs and the trade have
more sophisticated devices to work with? What measured values at what
distances would be unacceptable?
--
Al Poulin
--
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