RF Noise in the Neighborhood

[Douglas Furton]

Dear Electrafters,

Perhaps off topic, I write for advice tackling a problem that plagues my K2 and QTH: overwhelming RF noise from a source I cannot identify.

I've posted a screen shot of an o'scope trace of the IF output from a parlstar R30 showing the magnitude of this problem at the following URL.

http://gegenschein.wordpress.com/2010/10/18/rf-noise-in-the-neighborhood/

So, I’ve been working on tracking down the source of this noise. Here is what I know:

1) Noise is persistent, but not always present. Perhaps present 90% of the time, with no pattern.  When present, it is overwhelming.  My K2 noise blanker cannot blank it reliably.

2) Noise - 120 Hz pulses - is present from AM broadcast band to about 20 MHz.

3) Source is not in my house. I’ve turned off the main circuit breaker and operated from battery — noise still overwhelming.

4) Noise is on the neighborhood power lines.

5) I cannot locate a single source of the noise (walking around with a portable radio); as noted above, it is on the main power lines in the hood.

Please — any suggestions how I might track down this noise source and quiet it?  I first started noticing the problem about 6 months ago and it has grown steadily worse.  Now, I can't imagine how it could get worse.  I am just waiting, now, for whatever is the source to final go up in a puff of smoke (or move out of the neighborhood).

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[Jim Rogers, W4ATK]

Step 1:  If it syncs on line as your RFI does, it is Power Line  
Interference. Call you local power company. They will have the  
instrumentation to locate the source and if it is their problem they  
will fix it. If it is a subscriber's problem they will most likely  
identify the source.

Step 2. If step one fails then contact the RFI group at ARRL. Mike  
Gruber is on a first name basis with most of the utility companies and  
has a association with the FCC. The plan is, work with Mike and if all  
else fails then Mike will get the FCC involved.

This type of interference can propogate over the power lines for quite  
some distance. in my case it turned out to be a bad GFCI outlet in my  
neighbor's garage. Changed the outlet and problem solved.

73s Jim, W4ATK
On Oct 18, 2010, at 7:08 AM, Douglas Furton wrote:

> Dear Electrafters,
>
> Perhaps off topic, I write for advice tackling a problem that  
> plagues my K2 and QTH: overwhelming RF noise from a source I cannot  
> identify.
>
> I've posted a screen shot of an o'scope trace of the IF output from  
> a parlstar R30 showing the magnitude of this problem at the  
> following URL.
>
> http://gegenschein.wordpress.com/2010/10/18/rf-noise-in-the-neighborhood/
>
> So, I’ve been working on tracking down the source of this noise.  
> Here is what I know:
>
> 1) Noise is persistent, but not always present. Perhaps present 90%  
> of the time, with no pattern.  When present, it is overwhelming.  My  
> K2 noise blanker cannot blank it reliably.
>
> 2) Noise - 120 Hz pulses - is present from AM broadcast band to  
> about 20 MHz.
>
> 3) Source is not in my house. I’ve turned off the main circuit  
> breaker and operated from battery — noise still overwhelming.
>
> 4) Noise is on the neighborhood power lines.
>
> 5) I cannot locate a single source of the noise (walking around with  
> a portable radio); as noted above, it is on the main power lines in  
> the hood.
>
> Please — any suggestions how I might track down this noise source  
> and quiet it?  I first started noticing the problem about 6 months  
> ago and it has grown steadily worse.  Now, I can't imagine how it  
> could get worse.  I am just waiting, now, for whatever is the source  
> to final go up in a puff of smoke (or move out of the neighborhood).
>
> ____________________________________________________________
> Send any screenshot to your friends in seconds...
> Works in all emails, instant messengers, blogs, forums and social  
> networks.
> TRY IM TOOLPACK at http://www.imtoolpack.com/default.aspx?rc=if2 for  
> FREE
> ______________________________________________________________
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>
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> Please help support this email list: http://www.qsl.net/donate.html

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[HarrytheHam]

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[AC7AC]

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[pd0psb]

This clearly is PLC Powerline Comminication. Using HF over mains wires for wideband internet.
Especially the "home use" devices are terrible, called Homeplug.
Unfortunately our globe is flooded with these devices, sneaking through legislation everywhere.
Since mains wires are not defined as antennas these devices are type excepted.

http://en.wikipedia.org/wiki/Power_line_communication
http://www.qsl.net/dl5qe/plc.htm

Range is approximately 2-28MHz with a couple of notches around the amateurbands.

Speaking from experience the generated QRM is horrendous,
virtually wiping away shortwave entirely here.

73
Paul
PD0PSB

[Jim Brown-10]

  On 10/18/2010 5:08 AM, Douglas Furton wrote:
> Please — any suggestions how I might track down this noise source and quiet it?

There is a very good RFI email reflector, accessible from contesting.com.

I've written a tutorial on RFI. It's at
http://audiosystemsgroup.com/RFI-Ham.pdf

73, Jim K9YC
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[Eugene Balinski]

See the article in QST (Apr 2006, pp 41-46)  by Jim Hanson
W1TRC (SK) about the Ultrasonic RFI detector. Very helpful
in locating all sorts of interference issues.  I believe
that the design has been turned in to a kit.

73
Gene K1NR
K2 6K

On Mon, 18 Oct 2010 08:26:56 -0700
 "Ron D'Eau Claire" <[hidden email]> wrote:

> Many streetlights will do the same.
>
> Ron AC7AC
>
> -----Original Message-----
>
> The powerline noise was masking another
> noise source that was trashing everything from 80 up to
> 10m. This noise was
> about S5-7, but would cycle on an off....on for about 40
> seconds, off for
> about 20 seconds then back on.  .. Eventually
> tracked it down to my neighbor's sodium vapor flood
> lights. These lights are
> notorious for generating interference when they are on
> their last legs.  Had
> the rig on and observed his light flickering (noise
> present), going off
> (noise gone) and then coming back on (noise returned).
> Neighbor would not
> replace it until it eventually craped out....
>
> Harry WE1X
> --
>
>

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[Chris W7CTH]

I Guys, I know how frustrating this can be. I had the same problem with a power
line this last summer. You can have  noise miles away off of a power line on the
HF bands.

Most utility company's have a department to track down RFI interference. They
have equipment that will track it down to the insulator or bolt on a pole.
Most PLC's  Powerline Comminication  have been installed for many years. Most
PLC's are on mayor power lines and not on a normal over head line that is in the
Neighborhood. Plus they only send a TX signal for Blocking and or Tripping.

I understand if you have Internet over power lines, this can be a big problem.

Call you utility company, they can help clean it up.

Chris W7CTH


     
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