X-Mailer: Mozilla 4.8 [en] (Win98; U)
Subject: Re: Interference from power lines
Date: Mon, 06 Jan 2003 07:18:26 GMT
NNTP-Posting-Date: Sun, 05 Jan 2003 23:18:26 PST
Organization: EarthLink Inc. -- http://www.EarthLink.net
the degause switches got done in????
a wild guess
Kevin McMurtrie wrote:
> In article
> "Tom Del Rosso" wrote:
> >If anyone can make sense out of this, please reply.
> >On Wednesday, 1/1, the power lines right outside an office fell to the
> >street, still alive. They were repaired but the next day, in the office
> >of 11 computers, all but 3 monitors have wavy screens to various
> >degrees, from annoying to severe. The office is atop an incline, so
> >it's at the height of the power lines, but they are still 50 feet away.
> >The location is Long Island, NY, and the provider is LIPA. The
> >interference continued at least through Friday.
> >My first thought was magnetic interference, but there is no high-power
> >equipment inside, except for one unplugged electric heater. The
> >monitors least affected are on opposite sides of the office, and so are
> >the monitors most affected. Moving a monitor made no difference to it,
> >so there is no correlation with position within the room. (There is a
> >relation to vertical frequency, with lots of interference on one
> >previously good monitor when it was changed to low resolution (that
> >monitor doesn't display frequency unfortunately), but other monitors
> >were sensitive at all frequencies.)
> >Because it was spread out so, I thought it might be electrically rather
> >than magnetically coupled. The line voltage was a little unstable,
> >varying from 111 to 115 VAC from minute to minute. I was using a Fluke
> >79 (not true RMS). I tried unplugging 2 of the computers' UPSs and
> >letting them run on battery but there was no change in their
> >interference, so it must be magnetically coupled.
> >For the short time they were on battery, both UPS outputs dropped below
> >95 volts, so I guess they were left on and the batteries were killed
> >during the blackout. I considered that maybe the monitors were
> >permanently damaged, but unlikely I thought. In spite of the sudden
> >drop in voltage when switching to battery, the monitors I tested that
> >way didn't even twitch, but continued their steady low frequency waves.
> >If it's still happening Monday I'll try bringing in a new monitor. I
> >didn't get a chance to swap the best and worst of them, so I'd like to
> >try that too. Any other suggestions? What could cause that kind of
> >-If emailing please delete the first 3 words-
> Ask LIPA to fix it. There's something wrong with their wiring that's
> creating a long range electromagnetic field from the AC power. When
> everything is working correctly, the power lines are side by side and
> carrying matching amounts of power in and out. When they aren't, the
> magnetic fields don't cancel.
ps. reply to my earthlink account
same username at earthlink.net