Computer RFI problems-FARMERIK


Rik
 

My house hold computers are leaking RFI into the house wiring, and it is acting like an antenna for RFI where ever anything uses AC power.
I started looking around, and noticed at New Egg, some of the APC brand of outs/surge protectors sold for computers and home AV block 70 db of RFI. Also, split ferrite chokes can be fit over cables near computer devices. Higher ferrite mixture numbers are better for lower RF frequencies.

Anyone out there RFI proofed there house already, and have any pointers?

For now it looks like I should get RFI rated surge suppressors for each computer station and the server, as well as the TV and cable box. Also I should get a large number of the ferrite chokes for phone lines and all computer cables.

-FARMERIK


Peter Laws
 

On Wed, Jan 12, 2011 at 08:35, farmerik <farmerik@...> wrote:


Anyone out there RFI proofed there house already, and have any pointers?
http://audiosystemsgroup.com/RFI-Ham.pdf

This is hardly a FAQ, but it is a good tutorial on RFI. It's
ham-oriented, but RF is RF and a lot of it is receive oriented (as
opposed to RFI from your own transmitter, though that is covered,
too). I'm about a 1/3 of the way through it. :-)


--
Peter Laws | N5UWY | plaws plaws net | Travel by Train!


R. Mark Barnett
 

RFI is everywhere! I kept hearing a fuzzy "pulse" and traced it down to a battery powered Seiko wall clock. It seems like they stick a noisy processor in everything they make these days.

Thanks for the link!

Mark B.



> Anyone out there RFI proofed there house already, and have any pointers?

http://audiosystemsgroup.com/RFI-Ham.pdf

This is hardly a FAQ, but it is a good tutorial on RFI. It's
ham-oriented, but RF is RF and a lot of it is receive oriented (as
opposed to RFI from your own transmitter, though that is covered,
too). I'm about a 1/3 of the way through it. :-)

--
Peter Laws | N5UWY | plaws plaws net | Travel by Train!


Mike Mayer <mwmayer@...>
 

Peter,

 

I agree that the presentation you linked to is one of the best out there.

 

If you remember one thing it is that the suppression is proportional to the square of the number of turns. The typical clamp-on ferrite is one turn (the wire goes through once). If you look at some of the suggestions you will see multiple turns. Two turns is four times as good, three turns is 9 time as good, etc.

 

And yes, everything has either a noisy processor or a noisy switching power supply. That is why another option is to use an external antenna away from all of the noise sources in the house.

 

==========================================================
Mike Mayer
mwmayer@...


From: ultralightdx@... [mailto:ultralightdx@...] On Behalf Of Peter Laws
Sent: Wednesday, January 12, 2011 10:22 AM
To: ultralightdx@...
Subject: Re: [ultralightdx] Computer RFI problems-FARMERIK

 

 

On Wed, Jan 12, 2011 at 08:35, farmerik <farmerik@...> wrote:

> Anyone out there RFI proofed there house already, and have any pointers?

http://audiosystemsgroup.com/RFI-Ham.pdf

This is hardly a FAQ, but it is a good tutorial on RFI. It's
ham-oriented, but RF is RF and a lot of it is receive oriented (as
opposed to RFI from your own transmitter, though that is covered,
too). I'm about a 1/3 of the way through it. :-)

--
Peter Laws | N5UWY | plaws plaws net | Travel by Train!


Rik
 

It looks like the smaller mixture numbers are better for lower frequencies, so I had that wrong in my first post.
My focus is the AC house wiring, all circuits seem to be loaded with RFI. If I put a portable radio next to a filament bulb, I get tons of RFI when I switch it on, and the higher the bulb wattage, the more noise.
I started down this road when I had way too much noise in my Hammerlund HQ-100, even on the standby position, with no antenna connected.
Not much sense working on antennas, if the house is so full of RFI.

I did read that excellent article [tried to understand what I could] and went to the Fair-rite catalog. I don't see split chokes for LW and AM though. I see Delta make power filters for RFI, which may be what I need most. Thanks for the help, there is a lot to learn about this.
-FARMERIK

--- In ultralightdx@..., "Mike Mayer" <mwmayer@...> wrote:

Peter,



I agree that the presentation you linked to is one of the best out there.



If you remember one thing it is that the suppression is proportional to the
square of the number of turns. The typical clamp-on ferrite is one turn (the
wire goes through once). If you look at some of the suggestions you will see
multiple turns. Two turns is four times as good, three turns is 9 time as
good, etc.



And yes, everything has either a noisy processor or a noisy switching power
supply. That is why another option is to use an external antenna away from
all of the noise sources in the house.



==========================================================
Mike Mayer
mwmayer@...

_____

From: ultralightdx@... [mailto:ultralightdx@...] On
Behalf Of Peter Laws
Sent: Wednesday, January 12, 2011 10:22 AM
To: ultralightdx@...
Subject: Re: [ultralightdx] Computer RFI problems-FARMERIK





On Wed, Jan 12, 2011 at 08:35, farmerik <farmerik@...
<mailto:farmerik%40cox.net> > wrote:

Anyone out there RFI proofed there house already, and have any pointers?
http://audiosystemsgroup.com/RFI-Ham.pdf

This is hardly a FAQ, but it is a good tutorial on RFI. It's
ham-oriented, but RF is RF and a lot of it is receive oriented (as
opposed to RFI from your own transmitter, though that is covered,
too). I'm about a 1/3 of the way through it. :-)

--
Peter Laws | N5UWY | plaws plaws net | Travel by Train!


huelbe_garcia@fastimap.com <huelbe_garcia@...>
 

Hi Farmerik,

one of the most common sources of RFI (as noticed by colleagues here in
Brazil) are the Compact Fluorescent Lights (CFL). Some brands generate
lots of noise, other not that much. If you open one of these (be
careful) its base contains a high frequency, harmony rich oscillator.
Although the placeholders are marked in the circuit board, cheap brands
hardly install the inductors/capacitor meant to mitigate the RFI.

PY2WM DeMarco wrote an article specifically on CFL-generated noise and
how to solve it. The translated article (by Google Translator) is
available here:
http://tinyurl.com/4hfjqzt

the original article is here
http://py2wm.qsl.br/RFI/More_on_RFI_lamps/Filter.html

--hg

----- Original message -----
From: "farmerik" <farmerik@...>
To: ultralightdx@...
Date: Wed, 12 Jan 2011 19:34:38 -0000
Subject: [ultralightdx] Re: Computer RFI problems-FARMERIK

It looks like the smaller mixture numbers are better for lower
frequencies, so I had that wrong in my first post.
My focus is the AC house wiring, all circuits seem to be loaded with
RFI. If I put a portable radio next to a filament bulb, I get tons of
RFI when I switch it on, and the higher the bulb wattage, the more
noise.
I started down this road when I had way too much noise in my Hammerlund
HQ-100, even on the standby position, with no antenna connected.
Not much sense working on antennas, if the house is so full of RFI.

I did read that excellent article [tried to understand what I could] and
went to the Fair-rite catalog. I don't see split chokes for LW and AM
though. I see Delta make power filters for RFI, which may be what I need
most. Thanks for the help, there is a lot to learn about this.
-FARMERIK

--- In ultralightdx@..., "Mike Mayer" <mwmayer@...> wrote:

Peter,



I agree that the presentation you linked to is one of the best out there.



If you remember one thing it is that the suppression is proportional to the
square of the number of turns. The typical clamp-on ferrite is one turn (the
wire goes through once). If you look at some of the suggestions you will see
multiple turns. Two turns is four times as good, three turns is 9 time as
good, etc.



And yes, everything has either a noisy processor or a noisy switching power
supply. That is why another option is to use an external antenna away from
all of the noise sources in the house.



==========================================================
Mike Mayer
mwmayer@...

_____

From: ultralightdx@... [mailto:ultralightdx@...] On
Behalf Of Peter Laws
Sent: Wednesday, January 12, 2011 10:22 AM
To: ultralightdx@...
Subject: Re: [ultralightdx] Computer RFI problems-FARMERIK





On Wed, Jan 12, 2011 at 08:35, farmerik <farmerik@...
<mailto:farmerik%40cox.net> > wrote:

Anyone out there RFI proofed there house already, and have any pointers?
http://audiosystemsgroup.com/RFI-Ham.pdf

This is hardly a FAQ, but it is a good tutorial on RFI. It's
ham-oriented, but RF is RF and a lot of it is receive oriented (as
opposed to RFI from your own transmitter, though that is covered,
too). I'm about a 1/3 of the way through it. :-)

--
Peter Laws | N5UWY | plaws plaws net | Travel by Train!



------------------------------------

Yahoo! Groups Links


Russ Edmunds <wb2bjh@...>
 

I haven't yet found a split choke that works - at all.

I did find that switching to flat screen monitors reduced the RF pollution by almost half.

But I can't use a portable on AM or LW in the same room with the PC with even the flat screen on..

Russ Edmunds
15 mi NNW of Philadelphia
Grid FN20id

FM: Yamaha T-80 & Onkyo T-450RDS w/ APS9B @15'; Grundig G8
AM:  Modified Sony ICF 2010's barefoot


--- On Wed, 1/12/11, farmerik wrote:

From: farmerik
Subject: [ultralightdx] Computer RFI problems-FARMERIK
To: ultralightdx@...
Date: Wednesday, January 12, 2011, 9:35 AM

 

My house hold computers are leaking RFI into the house wiring, and it is acting like an antenna for RFI where ever anything uses AC power.
I started looking around, and noticed at New Egg, some of the APC brand of outs/surge protectors sold for computers and home AV block 70 db of RFI. Also, split ferrite chokes can be fit over cables near computer devices. Higher ferrite mixture numbers are better for lower RF frequencies.

Anyone out there RFI proofed there house already, and have any pointers?

For now it looks like I should get RFI rated surge suppressors for each computer station and the server, as well as the TV and cable box. Also I should get a large number of the ferrite chokes for phone lines and all computer cables.

-FARMERIK



Russ Edmunds <wb2bjh@...>
 

A major source is the controls for garage door openers - the sensors to prevent closure on pets and children radiate. Happily, the mfr of mine had substitutes available which do not !

Another is anything that has a thermostatically-controlled heater. That means that tropical fish and SM/LW DX don't mix.

Bad motor brushes on a furnace fan, air conditioner, washer, dryer or vacuum cleaner are other sources I've encountered.

Russ Edmunds
15 mi NNW of Philadelphia
Grid FN20id

FM: Yamaha T-80 & Onkyo T-450RDS w/ APS9B @15'; Grundig G8
AM:  Modified Sony ICF 2010's barefoot


--- On Wed, 1/12/11, R. Mark Barnett wrote:

From: R. Mark Barnett
Subject: Re: [ultralightdx] Computer RFI problems-FARMERIK
To: ultralightdx@...
Date: Wednesday, January 12, 2011, 11:58 AM

 

RFI is everywhere! I kept hearing a fuzzy "pulse" and traced it down to a battery powered Seiko wall clock. It seems like they stick a noisy processor in everything they make these days.

Thanks for the link!

Mark B.



> Anyone out there RFI proofed there house already, and have any pointers?

http://audiosystemsgroup.com/RFI-Ham.pdf

This is hardly a FAQ, but it is a good tutorial on RFI. It's
ham-oriented, but RF is RF and a lot of it is receive oriented (as
opposed to RFI from your own transmitter, though that is covered,
too). I'm about a 1/3 of the way through it. :-)

--
Peter Laws | N5UWY | plaws plaws net | Travel by Train!



Russ Edmunds <wb2bjh@...>
 

The HQ-100 is a single-conversion circuit, and its noise suppression is poor. I had one as my first communications receiver and I traded it in on a used HQ-150 pretty quickly.

An air core loop antenna is one of the better ways I've found to combat heavy RF - whether it's internal or external. But that's not always a viable solution.

Russ Edmunds
15 mi NNW of Philadelphia
Grid FN20id

FM: Yamaha T-80 & Onkyo T-450RDS w/ APS9B @15'; Grundig G8
AM:  Modified Sony ICF 2010's barefoot


--- On Wed, 1/12/11, farmerik wrote:

From: farmerik
Subject: [ultralightdx] Re: Computer RFI problems-FARMERIK
To: ultralightdx@...
Date: Wednesday, January 12, 2011, 2:34 PM

 

It looks like the smaller mixture numbers are better for lower frequencies, so I had that wrong in my first post.
My focus is the AC house wiring, all circuits seem to be loaded with RFI. If I put a portable radio next to a filament bulb, I get tons of RFI when I switch it on, and the higher the bulb wattage, the more noise.
I started down this road when I had way too much noise in my Hammerlund HQ-100, even on the standby position, with no antenna connected.
Not much sense working on antennas, if the house is so full of RFI.

I did read that excellent article [tried to understand what I could] and went to the Fair-rite catalog. I don't see split chokes for LW and AM though. I see Delta make power filters for RFI, which may be what I need most. Thanks for the help, there is a lot to learn about this.
-FARMERIK

--- In ultralightdx@..., "Mike Mayer" wrote:
>
> Peter,
>
>
>
> I agree that the presentation you linked to is one of the best out there.
>
>
>
> If you remember one thing it is that the suppression is proportional to the
> square of the number of turns. The typical clamp-on ferrite is one turn (the
> wire goes through once). If you look at some of the suggestions you will see
> multiple turns. Two turns is four times as good, three turns is 9 time as
> good, etc.
>
>
>
> And yes, everything has either a noisy processor or a noisy switching power
> supply. That is why another option is to use an external antenna away from
> all of the noise sources in the house.
>
>
>
> ==========================================================
> Mike Mayer
> mwmayer@...
>
> _____
>
> From: ultralightdx@... [mailto:ultralightdx@...] On
> Behalf Of Peter Laws
> Sent: Wednesday, January 12, 2011 10:22 AM
> To: ultralightdx@...
> Subject: Re: [ultralightdx] Computer RFI problems-FARMERIK
>
>
>
>
>
> On Wed, Jan 12, 2011 at 08:35, farmerik > > wrote:
>
> > Anyone out there RFI proofed there house already, and have any pointers?
>
> http://audiosystemsgroup.com/RFI-Ham.pdf
>
> This is hardly a FAQ, but it is a good tutorial on RFI. It's
> ham-oriented, but RF is RF and a lot of it is receive oriented (as
> opposed to RFI from your own transmitter, though that is covered,
> too). I'm about a 1/3 of the way through it. :-)
>
> --
> Peter Laws | N5UWY | plaws plaws net | Travel by Train!
>



ferrite61 <dxrx@...>
 

Yeah, computers are an RFI trash heap. If possible complete shut-down is the easiest cure (which is why I like Linux). I would go so far as to say unplug from the wall... the monitors also leak quite a bit. I have a UPS device, so its power off devices, power off UPS, and then unplug. Restart to desktop is about 90 seconds.

I would recommend this proceedure along with disconnect of broadband wire from wall to first device (at the first device) should noise reduction be insufficient. I note that the modems emminate quite a bit of hash also.

Its a good idea during thunderstorms also to protect the equipment!

Paul S. in CT (we got 20" snow at the house this morning!)

--- In ultralightdx@..., "farmerik" <farmerik@...> wrote:

My house hold computers are leaking RFI into the house wiring, and it is acting like an antenna for RFI where ever anything uses AC power.
I started looking around, and noticed at New Egg, some of the APC brand of outs/surge protectors sold for computers and home AV block 70 db of RFI. Also, split ferrite chokes can be fit over cables near computer devices. Higher ferrite mixture numbers are better for lower RF frequencies.

Anyone out there RFI proofed there house already, and have any pointers?

For now it looks like I should get RFI rated surge suppressors for each computer station and the server, as well as the TV and cable box. Also I should get a large number of the ferrite chokes for phone lines and all computer cables.

-FARMERIK


Rik
 

Update- I did order the surge protectors with 70 db of RFI blocking from 100 Kc. up. One unit for each computer and one for my radios and another for the TV and cable box. AC line filters should work in either direction, [I think]. The filter units are available on line, for anyone who wants to install them at the power input jack on most computers, or as a device which can be wired in series with the power leads in a device or box.
The chokes don't work much for LW and AM frequencies, and the RFI is throughout the household power wiring. I learned on line that a small water leak into an underground power feeder, [which I have from the road to my house], can also cause RFI. After I receive and install the new filtered outlet boxes, [APC P8VT3 R], I plan to post if that worked or not. - FARMERIK

--- In ultralightdx@..., "farmerik" <farmerik@...> wrote:

My house hold computers are leaking RFI into the house wiring, and it is acting like an antenna for RFI where ever anything uses AC power.
I started looking around, and noticed at New Egg, some of the APC brand of outs/surge protectors sold for computers and home AV block 70 db of RFI. Also, split ferrite chokes can be fit over cables near computer devices. Higher ferrite mixture numbers are better for lower RF frequencies.

Anyone out there RFI proofed there house already, and have any pointers?

For now it looks like I should get RFI rated surge suppressors for each computer station and the server, as well as the TV and cable box. Also I should get a large number of the ferrite chokes for phone lines and all computer cables.

-FARMERIK


Richard Bradley <rbswl@...>
 

I have the same problem, so I found unpluging the ac plug
from my comcast computer internet modem box when not
using and the problem was solved for me.
Rich
 
 


--- On Wed, 1/12/11, farmerik wrote:

From: farmerik
Subject: [ultralightdx] Computer RFI problems-FARMERIK
To: ultralightdx@...
Date: Wednesday, January 12, 2011, 9:35 AM

 
My house hold computers are leaking RFI into the house wiring, and it is acting like an antenna for RFI where ever anything uses AC power.
I started looking around, and noticed at New Egg, some of the APC brand of outs/surge protectors sold for computers and home AV block 70 db of RFI. Also, split ferrite chokes can be fit over cables near computer devices. Higher ferrite mixture numbers are better for lower RF frequencies.

Anyone out there RFI proofed there house already, and have any pointers?

For now it looks like I should get RFI rated surge suppressors for each computer station and the server, as well as the TV and cable box. Also I should get a large number of the ferrite chokes for phone lines and all computer cables.

-FARMERIK



Rik
 

Thanks for the tip. I went snooping around the basement, and found the surge protector/outlet box for the server, and all along the wiring back to the panel had a large amount of noise when I put the PL-310 nearby, tuned to a fairly weak AM station. I coiled the surge protector power cord into a number of turns, to form a choke, for now, since the new ones won't be here until next week. That did cut the noise by perhaps 50% upstairs.
I saw a number of other small things I could do too. For example, we have cable for Internet,telephone and TV, and the shielded cable for them has some RFI along it. I need to check the ground on that.
Some of the cables which connect the different computers run close to the server and surge protector much more than they could.

One other interesting thing I noticed was a huge boost in the AM signal when I got the PL-310 near the phone company ground for the old hard wired phone lines. Interesting! - FARMERIK

--- In ultralightdx@..., Richard Bradley <rbswl@...> wrote:






I have the same problem, so I found unpluging the ac plug
from my comcast computer internet modem box when not
using and the problem was solved for me.
Rich
 
 


--- On Wed, 1/12/11, farmerik <farmerik@...> wrote:


From: farmerik <farmerik@...>
Subject: [ultralightdx] Computer RFI problems-FARMERIK
To: ultralightdx@...
Date: Wednesday, January 12, 2011, 9:35 AM


 



My house hold computers are leaking RFI into the house wiring, and it is acting like an antenna for RFI where ever anything uses AC power.
I started looking around, and noticed at New Egg, some of the APC brand of outs/surge protectors sold for computers and home AV block 70 db of RFI. Also, split ferrite chokes can be fit over cables near computer devices. Higher ferrite mixture numbers are better for lower RF frequencies.

Anyone out there RFI proofed there house already, and have any pointers?

For now it looks like I should get RFI rated surge suppressors for each computer station and the server, as well as the TV and cable box. Also I should get a large number of the ferrite chokes for phone lines and all computer cables.

-FARMERIK