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[RFI] PC Reboot Problem

To: <rfi@contesting.com>
Subject: [RFI] PC Reboot Problem
From: Charles T Johnston" <ctj92@primenet.com (Charles T Johnston)
Date: Sat, 23 Oct 1999 08:32:17 -0700
It might not be RFI at all but a drop in the line voltage when that blower
comes on.  I have a UPS (uninterruptible power supply) on my computer. It
guards against outages but also kicks in or out at dips in the line keeping
the voltage constant to the computer. It also is the best surge protection
one can get.  I would bet your machine reboots because the voltage is
sagging at times.  My UPS is an APC Back Ups Pro 420.  To see several makes
and models of UPS's point your browser to  http://www.powerpros.com    If
this is your problem it is easily and inexpensively fixed by installing a
good UPS.

Charles T Johnston  - AB7SL
Charles' Ham Radio Pages

----- Original Message -----
From: P. M. Elliott <pelliott@flash.net>
To: <rfi@contesting.com>
Sent: Saturday, October 23, 1999 8:09 AM
Subject: [RFI] PC Reboot Problem

I don't know if this is actually an RFI problem, but wonder if anyone here
has run into it or has any thoughts.

Occasionally, 2 or 3 times a month, my shack computer reboots when my HVAC
system comes on.  It's a heat pump system.  Problem occurs summer and
winter.   Outdoor compressor kicks on first, no problem.  Blower comes on
half a minute later, PC resets.  Nothing else in the shack is affected.  The
shack is about 20 feet away from the air handler, and about 45 feet away
from the compressor outdoors.

I've tried a number of things. Replaced fan control relay. Put a snap-on
ferrite core around the blower wiring. I also changed to an electronic
(smart) thermostat along the way, but that made no difference in this
problem (and thankfully didn't introduce any birdies on the RX).  Broke into
the thermostat control wiring and put in ferrite wraps at roughly 6 foot
intervals.  I had already suppressed transmitter RFI to/from the PC (I had a
reboot problem on 160 TX, and RX birdies elsewhere).  Added ferrite to the
PC reset button wiring.  Even disconnected the reset button for awhile.
There is decent surge protection (commercial unit not a $9.95 cheapie) on
the shack circuit.

It's a bit hard to troubleshoot because I can't replicate the problem at
will.  Any thoughts appreciated.

Paul N3GPU

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