[Lowfer] PC noise reduction project ongoing here
Andy - KU4XR
ku4xr at yahoo.com
Mon Feb 1 15:00:13 EST 2010
Hi all:
Well still working on getting rid of the noise sources here
at my QTH. With the snow/ice storm last weekend, it made for
an opportune time to do some noise tracking vs. frequency to
determine which device is noisy, on what frequency. I found
out that the noises I have spread all across the spectrum,
are from multiple devices, and each has its own frequency it
sits on. SO !! one device at a time, I'm working to " Beef Up "
its internal filtering, along with the external Corcom filters
that I have installed now on just about everything noisy.
My daughter blew out the supply in her PC, I knew it wouldn't
hold long, so that forced me to install filtering in the
ORION SMPS that I had removed because of noise. I put in a
total of 32 MilliHenries of Inductance, and 2.5 MicroFarads
of capacitance. Reinstalled that supply, with the Corcom
external line filter, and now, not a trace of noise from that
used to be 20dB over S-9 noise maker. I have one more PC to
add filtering to the SMPS. An interesting note, after
putting the Corcom filter in the AC line of the CRT monitor
on my radio PC; It stopped the usual frequency changing buzzing
everytime the screen would change displays, and now the monitor
just emits a steady carrier at certain frequencies. No hash, or
wideband noise, just a carrier. I can turn the monitor off, and
the carrier goes away, turn it on, and it's back. The carrier
is about an S-7, not very strong, and at night if the static is
high, I can't tell it's there. Odd that it's just a carrier now.
The last of the major noise makers is the HDTV. Putting the
Corcom line filter on it reduced its noise from above S-9, to
S-7, so, since it has a SMPS too, After what I have witnessed
lately, The TV is due for some power supply " Beefing Up " too.
As Charlie - " COV " told me; this will take some time, and
looking. And he is right. It's turned out to be a Sleuthing
expedition.
Temps here are warming up again, but need a couple more days to
melt the ice, so the trees will stand back up, Then !! I'll
have some antenna work to do, getting the 1750 meter back up.
And the not so looked forward to job of cutting up, and removing
the downed trees from the back yard.
73 for now :::
Andy - KU4XR - EM75xr - Friendsville, TN.
LOWfer Beacon " XR " @ 185.29866 KHz ( QRSS-60 )
Coordinates: N: 35* 43' 54" - W: 84* 3' 16"
http://www.myspace.com/beaconxr
http://webpages.charter.net/ku4xr/
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