Hi,

Do receiving only (30 MHz on down) and presently just have a random length
wire running around attic.
Will be putting up an outside antenna once things warm up a bit.

Was wondering about household type of noise sources.

Not sure if the noise I'm picking up now is mainly from household sources
or atmospheric.
Other than turning stuff on and off, any easy way way to tell ?

Anyway, regarding household noise (other than on-off type of transients):

I imagine that the 60 Hz power stuff isn't much of a problem seeing where
most of the
listening is done.
Is this generally true, or are the higher order harmonics a problem ?

So, where is most of the noise coming from:
Is it Mainly from:

PC's
broadband cable modems
small 120 to 12 V type of wal-warts
Or,... ?

Any filters or other approaches to minimize ?

Trying to get a good understanding on this: How quickly do the fields from
these sources diminish with distance
(I would imagine very quickly, but am not sure) ?

Thanks,
Bob

If you can operate your receiver off battery power, I suggest shutting
off all the power at your circuit breaker. Then turn your receiver on
and see how much 'quieter' things are. That should show you how much of
the noise you hear is atmospheric and how much of it is from sources
inside the house.

If you want to minimize the noise coming from various appliances in
your home, pick up some ferrite beads and attach them to all the power
cords. I did this and it helps. I also keep my receivers as far away
from other appliances, especially computers, printers, etc., as
possible. Yes, this might mean that you won't be able to control the
receiver with your computer, but--at least in my case--the trade off
was well worth it.

Who sells ferrite beads,websites Please? Concerning computers,I wonder
if making some Faraday cages (for computer and computer monitor) out of
some easy to shape and form close weave copper screen wire would help?
Something that can easily be placed over (and removed for when using
computer and computer monitor) computer and computer monitor and perhaps
shape some copper screen wire around whatever computer related
cables/wires would be of any help with decreasing RFI? Well,it's a
thought anyway,I guess.Hey,I certainly am not an expert on that.
cuhulin

wrote in message
...
Who sells ferrite beads,websites Please? Concerning computers,I wonder
if making some Faraday cages (for computer and computer monitor) out of
some easy to shape and form close weave copper screen wire would help?
Something that can easily be placed over (and removed for when using
computer and computer monitor) computer and computer monitor and perhaps
shape some copper screen wire around whatever computer related
cables/wires would be of any help with decreasing RFI? Well,it's a
thought anyway,I guess.Hey,I certainly am not an expert on that.
cuhulin

This would do nothing to diminish the H field.

W4OP

On Fri, 20 Jan 2006 07:52:03 -0500, "Robert11"
wrote:

Hi,

Do receiving only (30 MHz on down) and presently just have a random length
wire running around attic.
Will be putting up an outside antenna once things warm up a bit.

Was wondering about household type of noise sources.

Not sure if the noise I'm picking up now is mainly from household sources
or atmospheric.
Other than turning stuff on and off, any easy way way to tell ?

Anyway, regarding household noise (other than on-off type of transients):

I imagine that the 60 Hz power stuff isn't much of a problem seeing where
most of the
listening is done.
Is this generally true, or are the higher order harmonics a problem ?

So, where is most of the noise coming from:
Is it Mainly from:

PC's
broadband cable modems
small 120 to 12 V type of wal-warts
Or,... ?

Any filters or other approaches to minimize ?

Trying to get a good understanding on this: How quickly do the fields from
these sources diminish with distance
(I would imagine very quickly, but am not sure) ?

Thanks,
Bob


Dimmers. Halogen lamps. Miniature neon lamps (doorbell buttons,
fish-tank heaters). Old fashioned fluorescent lamps. Neon lighting.
Electric blankets. Waterbed heaters.

PC's
broadband cable modems
small 120 to 12 V type of wal-warts
Or,... ?

All of the above. But some comments:

Monitors can make a lot of harmonic hash throughout the HF spectrum.
TV's don't seem quite so bad in general (3.58MHz and harmonics are of
course a problem!) and I don't know much about HDTV's etc.

Most wall-warts don't make a lot of noise, but small switching supplies
are an exception.

Fluorescent lamps and dimmers can make an awful racket. Electronic
ballasts make a qualitatively different kind of hash than magnetic
ballasts. Some low-voltage DC lighting and halogen lamps make
incredible noise, I have no idea why (maybe a built-in dimmer?)

Ethernet cabling running around the house can make some, especially
concentrated at 10MHz and harmonics.

Noise can be conducted over and radiated by power cables, ethernet
cables, video cables, keyboard cables, etc.

Motors can always be a source. Kitchen appliances are awful but not
usually run for more than a few minutes at a time. Vacuum cleaners can
be almost as bad. Furnace blowers, AC compressors, refrigerator
compressors aren't as awful but in a modern house at least one of these
is probably running somewhere.

Sometimes I fantasize about moving out to the middle of nowhere, where
there is no power grid!

Tim.

"Robert11" wrote in message
...
Hi,

Do receiving only (30 MHz on down) and presently just have a random length
wire running around attic.
Will be putting up an outside antenna once things warm up a bit.

Was wondering about household type of noise sources.

Not sure if the noise I'm picking up now is mainly from household sources
or atmospheric.
Other than turning stuff on and off, any easy way way to tell ?

Turning stuff on and off is the easiest way to tell
if it is making noise.


Anyway, regarding household noise (other than on-off type of transients):

I imagine that the 60 Hz power stuff isn't much of a problem seeing where
most of the
listening is done.
Is this generally true, or are the higher order harmonics a problem ?

So, where is most of the noise coming from:
Is it Mainly from:

PC's
broadband cable modems
small 120 to 12 V type of wal-warts
Or,... ?

Any filters or other approaches to minimize ?

Trying to get a good understanding on this: How quickly do the fields
from these sources diminish with distance
(I would imagine very quickly, but am not sure) ?

1/r^2


Thanks,
Bob

I've got a Sony component AM/FM/stereo amplifier
that makes a fair amount of noise whenever it it
plugged in. (Switch-mode power supply with
poor filtering apparently.)

The computer monitor makes a fair amount of
noise too. (It is hard to shield a CRT.)

I haven't specifically tracked down
other sources in the house.
The situation was pretty poor when I just had
an indoor antenna.
So I quickly put up an outdoor antenna with
coaxial feed. That made a big difference.

I still hear some low level noise spaced every
62 kHz or so throughout the HF band.
It is not in my house but it might be in
the neighborhood.
Some day I'll get a directional antenna and
portable receiver and track it down.

--
rb

In article ,
Ron Baker, Pluralitas! wrote:

I still hear some low level noise spaced every
62 kHz or so throughout the HF band.
It is not in my house but it might be in
the neighborhood.
Some day I'll get a directional antenna and
portable receiver and track it down.

A VGA display running at one of the lower res 31 kHz horizontal scan rates.

Mark Zenier
Googleproofaddress(account:mzenier provider:eskimo domain:com)

"Mark Zenier" wrote in message
...
In article ,
Ron Baker, Pluralitas! wrote:

I still hear some low level noise spaced every
62 kHz or so throughout the HF band.
It is not in my house but it might be in
the neighborhood.
Some day I'll get a directional antenna and
portable receiver and track it down.

A VGA display running at one of the lower res 31 kHz horizontal scan
rates.

Interesting idea.
But I've never noticed the noise change character.
One would think that a VGA display would be
turned off occasionally.

The noise is unchanged even if my monitor is
unplugged and every circuit breaker in the house, except
for that of the radio, is switched off.

If it is from a display it would have to be from
a defective one. Every display has a horizontal
in the tens of kHz range. We are not inundated
with display noise.

--
rb

In article ,
Ron Baker, Pluralitas! wrote:

"Mark Zenier" wrote in message
...
In article ,
Ron Baker, Pluralitas! wrote:

I still hear some low level noise spaced every
62 kHz or so throughout the HF band.
It is not in my house but it might be in
the neighborhood.
Some day I'll get a directional antenna and
portable receiver and track it down.

A VGA display running at one of the lower res 31 kHz horizontal scan
rates.

Interesting idea.
But I've never noticed the noise change character.
One would think that a VGA display would be
turned off occasionally.

The noise is unchanged even if my monitor is
unplugged and every circuit breaker in the house, except
for that of the radio, is switched off.

If it is from a display it would have to be from
a defective one. Every display has a horizontal
in the tens of kHz range. We are not inundated
with display noise.

I've noticed that the spurs from CRT display horizontal drive usually
peak at a frequency spacing of twice the scan rate.

Another possible is a compact fluorescent lamp.

Mark Zenier
Googleproofaddress(account:mzenier provider:eskimo domain:com)