Elecraft › [HAM]

Tracking down S9+ noise on 40M

Classic

List

Threaded

8 messages Options

David Dietrich

Tracking down S9+ noise on 40M

Hi All,

Could someone please explain the proper way to track down RF noise in and around my house? More often than not, I always have S9+ noise on 40 Meters, making anything but really strong signals (S9+) audible above the noise. I have only had a few instances where the noise was below S9 on 40. I know I have to power down the house and then bring it up one circuit at a time with my radio on battery power. I also know I am supposed to use a handheld AM radio to listen as I walk around the house. I don't know what I should be listening for, or where to tune on AM to hear what I am supposed to hear. Now that I am getting back into operating more regularly, I would really like to see where some of this noise is coming from; and reduce or eliminate it if at all possible even if it means shutting something off while I am on the air.

73,

David, KC9EHQ
K1-4 s/n 2051
K2/10 s/n 7164
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

riese-k3djc

Re: Tracking down S9+ noise on 40M

light dimmers
touch on off lamps
plasma tv sets

bob k3djc

On Wed, 18 Jan 2012 19:41:33 -0800 (PST) David Dietrich
<[hidden email]> writes:

> Hi All,
>
> Could someone please explain the proper way to track down RF noise
> in and around my house? More often than not, I always have S9+
> noise on 40 Meters, making anything but really strong signals (S9+)
> audible above the noise. I have only had a few instances where the
> noise was below S9 on 40. I know I have to power down the house and
> then bring it up one circuit at a time with my radio on battery
> power. I also know I am supposed to use a handheld AM radio to
> listen as I walk around the house. I don't know what I should be
> listening for, or where to tune on AM to hear what I am supposed to
> hear. Now that I am getting back into operating more regularly, I
> would really like to see where some of this noise is coming from;
> and reduce or eliminate it if at all possible even if it means
> shutting something off while I am on the air.
>
> 73,
>
> David, KC9EHQ
> K1-4 s/n 2051
> K2/10 s/n 7164
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>

____________________________________________________________
53 Year Old Mom Looks 33
The Stunning Results of Her Wrinkle Trick Has Botox Doctors Worried
http://thirdpartyoffers.juno.com/TGL3141/4f1792f2df36aeb0em03vuc
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

K1FFX

Re: Tracking down S9+ noise on 40M

In reply to this post by David Dietrich

You might also be on the lookout for failing street lamps out in your neighborhood. I'm not sure what the technology is where I live, but when a street lamp starts to fail, as evidenced by its cutting out for a while and then reiighting ... when the lamp is in its cut-out state, it generates horrific RF noise on 40 meters (and below). A call to the local power company (with the pole number) ... they come and replace the lamp fixture ... has always fixed the problem

- Bruce

Bruce Rosen
K1FFX
K2/100 6982 KSB2 KAT100-1 KAF2 KIO2

Bob K6UJ

Re: Tracking down S9+ noise on 40M

In reply to this post by David Dietrich

Dave,

I don't think you will need the AM radio unless you discover it is not in your house. Here's what I would do:
* run the K3 on battery power, have it tuned to 40 meters where you have the noise.
* Turn off the main breaker to the house. Go check the K3, did the noise go away ? If it did the noise source is in your house. If it didn't then it is AM radio search time. (we can
go over sleuthing with an AM radio in the neighborhood later if needed, hopefully you won't)
* If it did then turn on each breaker one at a time, checking each time at the K3. The noise will reappear when the circuit breaker is turned on having the noise generator.
* Check them all, it could be on more than one circuit.
* Then leave the offending circuit on and go around and unplug, one at a time all the devices on the circuit, checking each time with the K3. It will go away when the offender is
unplugged. You need to actually unplug each device not just turn them off, (my DirecTV receiver was a noise generator even when it was turned off the power supply was
generating noise.)

Hopefully it is in your house where you can remedy it easily. I do this every once in a while myself. My last check discovered one of the kids external hard drives was a nasty
noise generator. Another time one of the battery chargers to my Makita cordless drill was a culprit. If you have any touch control lamps, I can almost guarantee they are nasty.

good luck and let us know how you do.

73,
Bob
K6UJ

On Jan 18, 2012, at 7:41 PM, David Dietrich wrote:

> Hi All,
>
> Could someone please explain the proper way to track down RF noise in and around my house? More often than not, I always have S9+ noise on 40 Meters, making anything but really strong signals (S9+) audible above the noise. I have only had a few instances where the noise was below S9 on 40. I know I have to power down the house and then bring it up one circuit at a time with my radio on battery power. I also know I am supposed to use a handheld AM radio to listen as I walk around the house. I don't know what I should be listening for, or where to tune on AM to hear what I am supposed to hear. Now that I am getting back into operating more regularly, I would really like to see where some of this noise is coming from; and reduce or eliminate it if at all possible even if it means shutting something off while I am on the air.
>
> 73,
>
> David, KC9EHQ
> K1-4 s/n 2051
> K2/10 s/n 7164
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

W2BLC

Re: Tracking down S9+ noise on 40M

Excellent down to earth logical method - thanks for sharing.

Bill W2BLC

--
Sent from my blackboard - written in chalk

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

k1htv

Re: Tracking down S9+ noise on 40M

In reply to this post by riese-k3djc

And don't forget ELECTRIC BLANKETS! I just found the source of a loud noise
which appeared to be emanating from a neighbor's house. The noise source turned
out to be an electric blanket with independent control boxes and control units
(rotary controls). Each box was causing either a loud click every second or a
loud AC buzzzzzz when the electric blanket's control was set to call for more
heat. I took a portable Sony AM/FM/SW radio with me to the neighbor's house and
walked around the inside the house with him. At the far end of the house the
signal was moderately loud with the antenna collapsed while listening on 10
Meters. When we got to the master bedroom, the signal got noticeably louder.
Unplugging the AC from one box stopped one of the clicks/buzzes. Unplugging the
second box produced silence. In the bedroom, the noises could also be heard on
broadcast band frequencies, but were not very strongly in the AM BC band outside
the house.

The frequencies with the strongest signal from a noise source is often related
to the length of the wires attached to it. In this case, the signals seemed to
peak on higher frequencies in the 6M and 10M bands. In the case of a noisy power
line, where the wires are attached to arcing hardware are physically longer, you
can expect to have stronger signals on the lower frequencies. But even with
power lines, in addition to using an AM BC radio, it is often helpful to use a
portable radio that can tune in the 108-130 MHz AM aircraft band to find noise
sources on power line poles.

In your case, if you can hear the noise on a portable AM radio at the breaker
panel, try killing power to one breaker at a time to see which one kills the
noise. Good luck in playing noise detective!

73,
Rich - K1HTV

= = =

From: [hidden email] [mailto:[hidden email]]
Sent: Wednesday, January 18, 2012 22:49 PM
To: [hidden email]
Cc: [hidden email]
Subject: Re: [Elecraft] Tracking down S9+ noise on 40M

light dimmers
touch on off lamps
plasma tv sets

bob k3djc

On Wed, 18 Jan 2012 19:41:33 -0800 (PST) David Dietrich <[hidden email]>
writes:
> Hi All,
>
> Could someone please explain the proper way to track down RF noise in
> and around my house?
.....

>
> 73,
>
> David, KC9EHQ

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Eugene Balinski

Re: Tracking down S9+ noise on 40M

Printers. They need to be **unplugged** and not just off.
My HP blasts a lot of noise on 40 when just "off".

Washing Machines, especiallly the new ones with micro
processors

Door bell transformers. Lots and lots of stories there.
Google is your friend.

Outdoor Christmas lights although the season is over

Arcing/cracked power line insulators. See various QST
articles on how to track down and how to build an
Ultrasonic detectror. One of the best ones was designed by
Jim Hanson W1TRC (SK). Sometimes you can just stand
outside and hear them especially in wet/foggy wx.

Street Lights although they usually only manifest
themselves at night

Bad flourscent light fixtures

touch lamps

Neon Lights if you live in a more urban environment

Electric fenses if you live in a rual area

These are just a few that come to mind. Please do report
back to the group what/if you find.

73
K1NR

On Thu, 19 Jan 2012 13:02:42 -0500
"Rich - K1HTV" <[hidden email]> wrote:

> And don't forget ELECTRIC BLANKETS! I just found the
> source of a loud noise
> which appeared to be emanating from a neighbor's house.
> The noise source turned
> out to be an electric blanket with independent control
> boxes and control units
> (rotary controls). Each box was causing either a loud
> click every second or a
> loud AC buzzzzzz when the electric blanket's control was
> set to call for more
> heat. I took a portable Sony AM/FM/SW radio with me to
> the neighbor's house and
> walked around the inside the house with him. At the far
> end of the house the
> signal was moderately loud with the antenna collapsed
> while listening on 10
> Meters. When we got to the master bedroom, the signal got
> noticeably louder.
> Unplugging the AC from one box stopped one of the
> clicks/buzzes. Unplugging the
> second box produced silence. In the bedroom, the noises
> could also be heard on
> broadcast band frequencies, but were not very strongly in
> the AM BC band outside
> the house.
>
> The frequencies with the strongest signal from a noise
> source is often related
> to the length of the wires attached to it. In this case,
> the signals seemed to
> peak on higher frequencies in the 6M and 10M bands. In
> the case of a noisy power
> line, where the wires are attached to arcing hardware are
> physically longer, you
> can expect to have stronger signals on the lower
> frequencies. But even with
> power lines, in addition to using an AM BC radio, it is
> often helpful to use a
> portable radio that can tune in the 108-130 MHz AM
> aircraft band to find noise
> sources on power line poles.
>
> In your case, if you can hear the noise on a portable AM
> radio at the breaker
> panel, try killing power to one breaker at a time to see
> which one kills the
> noise. Good luck in playing noise detective!
>
> 73,
> Rich - K1HTV
>
> = = =
>
> From: [hidden email] [mailto:[hidden email]]
> Sent: Wednesday, January 18, 2012 22:49 PM
> To: [hidden email]
> Cc: [hidden email]
> Subject: Re: [Elecraft] Tracking down S9+ noise on 40M
>
> light dimmers
> touch on off lamps
> plasma tv sets
>
> bob k3djc
>
> On Wed, 18 Jan 2012 19:41:33 -0800 (PST) David Dietrich
> <[hidden email]>
> writes:
> > Hi All,
> >
> > Could someone please explain the proper way to track
> down RF noise in
> > and around my house?
> .....
>
> >
> > 73,
> >
> > David, KC9EHQ
>
>
>
>

______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list:
> http://www.qsl.net/donate.html

---------------------------------------------------------------------
Web mail provided by NuNet, Inc. The Premier National provider.
http://www.nni.com/
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

Bill Hammond

Re: Tracking down S9+ noise on 40M

In reply to this post by David Dietrich

My biggie was the dishwasher...documented here: http://www.flickr.com/photos/ak5x/6595335923/in/photostream
Electronic motor control seems to be the latest QRN maker, or would Plasma TV's win that award?...My noise was from DC to Daylight all bands S9. The P3 was very handy in tracking this down.

With a AM radio the buzz will get louder the closer you are to the offending device. BC radios usually have some null points off the end of the ferrite BC antennas giving you some directivity. There are some tips in the ARRL RFI 3rd edition that are helpful, as well as the AC Power Interference Handbook by Loftness, KB7KK. These are good reference books to have. A quick glance at "The Handbook" index did not show RFI as a covered subject, but I may of missed it.

Powering down the house is helpful but not if the offending device is on batteries :)

On Jan 18, 2012, at 9:41 PM, David Dietrich wrote:

Bill Hammond
[hidden email]
Bill Hammond-AK5X
[hidden email]
[hidden email]
K3 #69
P3 #817
KPA500 # 149
K2/100 #4637
K1 #2033
KX1 #1023
T1

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html