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@sbcglobal.net>
To: herbs@vitelcom.net; steve.root@culligan4water.com; 'TopBand List'
<topband@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@contesting.com
[mailto:topband-bounces@contesting.com]
On Behalf Of Herb Schoenbohm
Sent: Tuesday, December 22, 2009 2:56 PM
To: steve.root@culligan4water.com; TopBand List
Subject: Re: Topband: Power Line Noise
steve.root@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
_______________________________________________
"160-meters is a band for men, not for sissies!" - SM5EDX
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