Topband: Power Line Noise

[w2pm at aol.com]

Another bad actor with household noise which  will hurt 160 and even 
higher bands are water bed warmers.  Found several already for friends 
over the years.  Noise is pulsed white noise or other pulsed crud even 
if the warmer is OFF! Only cure is to pull plug out of wall outlet or 
put it on a switched outlet.   I have never found clamp on chokes to be 
effective here but once had a VCR radiating crud on 80 meters and wound 
the electrical cord for it through a 4 inch diameter donut toroid and 
it stopped it.

2 other chronic QRM'ers here are the electrostatic airfilters which 
sound like those outdoor bug zappers.  They pulse out a modulated 
carrier for 4 seconds - off 5 seconds, on 4 seconds - and the carriers 
fall on discrete frequenices from 160 up.  Toroids did not work because 
the RF is actually radiating from the unit.  I did find that wrapping 
my hand over the upper part of the plastic tower-like housing changed 
and muted the crud big-time so now I put a sheet of alum foil on that 
spot and it took most of the crud out.

Pete W2PM

-----Original Message-----
From: Dave Harmon <k6xyz at sbcglobal.net>
To: herbs at vitelcom.net; steve.root at culligan4water.com; 'TopBand List' 
<topband at contesting.com>
Sent: Thu, Dec 24, 2009 4:36 pm
Subject: Re: Topband: Power Line Noise


I got a MFJ model 852 line noise meter and found almost all of my noise 
in
10 minutes.
The dishwasher was making a loud racket almost like white 
noise.....wait, it
wasn't running!
The indicators, processors and other lectronic stuff in the door are 
still
running if the door is closed. To stop this noise I just unlocked the 
door.
Next, the coffee pot was making an even louder noise so I went to the 
junk
box and found an MFJ snap on ferrite. I put as many turns as I could of 
the
line cord through it at the back of the pot....gone.
Next....I found several wall warts that I never use that were making
noise.....unplugged them.
Then, there is a USB hub off the back of the computer that was tearing 
up
160mtrs so I discovered that the hub doesn't need to have wall wart 
power
because it is powered by the USB on the computer....duhhhh....threw that
wart away.
Anyway...that's a few things that cleared up noise around here.
I don't have any o' them new fangled light bulbs either.
For power line noise, just drive around and you will soon find the poles
that are causing your problems

Regards

Dave Harmon
K6XYZ[at]sbcglobal[dot]net
Sperry, Ok.

-----Original Message-----
 From: topband-bounces at contesting.com 
[mailto:topband-bounces at contesting.com]
On Behalf Of Herb Schoenbohm
Sent: Tuesday, December 22, 2009 2:56 PM
To: steve.root at culligan4water.com; TopBand List
Subject: Re: Topband: Power Line Noise



steve.root at culligan4water.com wrote:
> So Old blue helped find noise sources that were a mile and a half 
away? I
can't begin to tell you all how discouraging that is....
>
> The noise here is incredible. The K3 noise blanker, set to it's most
aggressive level, has no effect on it. I spent a year experimenting 
with the
MFJ-1026 and never was able to achieve any kind of a null, much less one
that improved S/N ratio. The noise sounds like a waterfall, it has no
discernable characteristics when seen on a 'scope.


Steve,

Maybe more of us could help if you made a .mpg recording of the noise
with the RX in the AM mode and with a 9Khz B/W and then post it on a 
web
site where we all can listen to it and see if we can provide any clues
to what could produce this noise. I am certain there is some noise
sleuth out there that has heard this type of noise before and can
provide a few clues which will narrow down the search.  Additionally 
you
should cut the main breaker going to your house while having your 160
meter radio power by a DC source.

Are you near an industrial area? Are there any oil fired furnaces
nearby?  Start you own check list and determine items like time and
temperature.  If none exists it eliminates potential sources and gives
credence to other possibilities..  Just don't give up as it can be
found.  An aircraft capable scanner (AM mode) with a small Yagi can be
very helpful in DF'ing multiple source noise, sometimes better than an
ultra-sonic detector.

Merry Christmas and I hope a solution is under the tree this year,

herb Schoenbohm, KV4FZ
_______________________________________________
160 meters is a serious band, it should be treated with respect. - TF4M

_______________________________________________
160 meters is a serious band, it should be treated with respect. - TF4M