Computer Noise ruining 20 & 30m

[Alan D. Wilcox, W3DVX]

Hello,
I gave away the feeble old PC I had by my radio equipment and replaced
it with a newer one ...

Now I have S9+ noise wiping out 20 and 30 meters.

Using same keyboard, mouse, monitor; just the PC in a new case.
Evidently it has a
noisy switcher supply in it. Tried 110V in-line filter, also different
110V house circuit,
but still have noise. Grounds don't help. Don't happen to have a box of
toroids for chokes.

I've got an old PC supply or two in the junk box, but hoping something
else might fix.

Any thoughts on an easy fix?

Thanks,
Alan

Alan D. Wilcox, W3DVX
570-321-1516
http://WilcoxEngineering.com
Williamsport, PA 17701

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[M0XDF]

All reports of fixing this I've seen are to replace the PSU - people go to
their local friendly PC shop and explain the problem and get a quiet PSU.

I haven't done this myself because I have a Mac - not saying they are
quieter, just I haven't had a problem.


On 11/1/08 15:03, "Alan D. Wilcox" <[hidden email]> sent:

> Hello,
> I gave away the feeble old PC I had by my radio equipment and replaced
> it with a newer one ...
>
> Now I have S9+ noise wiping out 20 and 30 meters.
>
> Using same keyboard, mouse, monitor; just the PC in a new case.
> Evidently it has a
> noisy switcher supply in it. Tried 110V in-line filter, also different
> 110V house circuit,
> but still have noise. Grounds don't help. Don't happen to have a box of
> toroids for chokes.
>
> I've got an old PC supply or two in the junk box, but hoping something
> else might fix.
>
> Any thoughts on an easy fix?
>
> Thanks,
> Alan

--
I have never met a man so ignorant that I couldn't learn something from
him. -Galileo Galilei, physicist and astronomer (1564-1642)



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[Ed Gray W0SD]

I realize this is not a specific Elecraft topic but it is in response to
a request and it is on a radio subject.  It would be interesting on
reports on what the K3 noise blankers do on this type of noise.

First of all I am no engineer but I have had some experience with this
problem.

I got the top of the line Carcom line filter based on suggestions on the
160 reflector and installed it right to the PC with about 1 inch of line
cord and I put ferrite on that 1 inch.  I knocked the noise down a
bunch,  I have to do some testing on a dead band to see if it is all
gone but it made a huge improvement.  I have to suspect your AC line
filter is not a very good one OR the case is leaking.  I say this
because using the AC line filter seems to be the common cure that works.
  Fortunately my case was metal but on a lot of the new computers there
is a lot of the case that is plastic.   For me the problem was the worst
on 160 meters.  From my tests the noise was coming in over the antenna

I was going to switch computer power supplies but my old ones did not
provide the extra voltage line that most of the newer supplies do and
that my mother board required.  If I remember correctly the extra line
had to do with the dual processor.  It is kind of a catch 22 as the
newer supplies that plug into the newer computers just are not built
like they were for filtering.  I am hoping someone can suggest a power
supply that work with the newer computers that can be bought from places
like Tiger direct etc. that is well built and quiet.  One hates to buy a
new supply and have the same problem and from what I can tell the odds
of that happening are pretty high..  One could try and determine the
noise level on a broadcast receiver and then go to a friendly computer
shop and try some supplies until you found a quiet one on the broadcast
receiver.  That might not be all that cheap if you have to try several
and take up a lot of time.  It seems to me buying one that is of good
design that others have not had problems with would make the most sense
if one knew which one to buy. .  Another approach is if someone would
buy a supply and fix it and then document what supply it was and how
they fixed it with filtering and toroids it would be a great service as
this problem is going to be  become very common as us hams update our
computers.  Actually I suspect they are all built about the same so what
worked on one would work on all of them.  A good article for one of the
ham magazine but for now it could be on a web site.

I will be interested in what others say.

Another common problem is birdies from the Router and CAT5E cable.  I am
digging into that,  here they seem to be on all the bands spread out.  
One can work around them but I want to get rid of them.  Toroids seem to
be one answer as a lot of routers have this problem.  Again if someone
knows of a router that is clean that would be an easier fix as some of
the big toroids are not cheap.  I guess one could buy various routers
and take them back within the 30 day return period until you found a
clean one but it sure would save a lot of hams a lot of trouble to know
of one that is clean.  I would be interested in what others say on this
subject.

Thanks

Ed W0SD


>
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[Julian, G4ILO]

Alan D. Wilcox wrote

Hello,
I gave away the feeble old PC I had by my radio equipment and replaced
it with a newer one ...

Now I have S9+ noise wiping out 20 and 30 meters.

Using same keyboard, mouse, monitor; just the PC in a new case.
Evidently it has a
noisy switcher supply in it. Tried 110V in-line filter, also different
110V house circuit,
but still have noise. Grounds don't help. Don't happen to have a box of
toroids for chokes.

It's very likely to be the power supply, especially if it is a home build or a local PC store build rather than a branded model. Most of the PC cases and power supplies that home builders and small assemblers use are made in China, and the manufacturers often leave out all the components they can get away with, like anything to do with interference suppression. I remember someone a few years ago took apart a noisy power supply and could see all the holes in the PC board where the suppression components should have been. It was quite an eye opener.

Replace it with a power supply from a decent manufacturer and all should be OK.

[Alan D. Wilcox, W3DVX]

SOLVED!
Just replaced the 400w supply with a 300w that I had in the junk box.
Both foreign cheap
units, but that's all the local PC shops seem to carry (at least at my
QTH). The replacement
is nicely quiet ... and a lot easier fix than what I was dreading!

Now that I can hear the radio properly, back to doing the remote audio
with HRD.

Thanks for the help!
Alan
------------------------------------------------------------------------

Alan D. Wilcox wrote:

> Hello,
> I gave away the feeble old PC I had by my radio equipment and replaced
> it with a newer one ...
>
> Now I have S9+ noise wiping out 20 and 30 meters.
>
> Using same keyboard, mouse, monitor; just the PC in a new case.
> Evidently it has a
> noisy switcher supply in it. Tried 110V in-line filter, also different
> 110V house circuit,
> but still have noise. Grounds don't help. Don't happen to have a box
> of toroids for chokes.
>
> I've got an old PC supply or two in the junk box, but hoping something
> else might fix.
>
> Any thoughts on an easy fix?
>
> Thanks,
> Alan
>
> Alan D. Wilcox, W3DVX
> 570-321-1516
> http://WilcoxEngineering.com
> Williamsport, PA 17701

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[Bill VanAlstyne W5WVO]

One thing to be aware of -- and I too have had quite a bit of undesired
experience in this area -- hash from switching power supplies in computers is
typically common mode noise, not differential noise. Consequently, a
differential line filter often won't knock it down very much, if at all. What
you need is ferrite toroids -- big ones -- around and through which you wind
the power cord. In my case, the computer power supply is a 470W job in an ATX
form factor, and because of the high power components, there wasn't any room
in the PS case for filtering! So the RF noise from this PS was horrendous. It
took TWO large ferrite donuts in series, with the ENTIRE power cord wound
around them, to suppress the noise on 6M. I had bought a rather expensive
differential noise filter for the line, and it did absolutely nothing.
Brute-force common-mode filtering using ferrite toroids will usually cure the
problem, but you may need a lot more saturability than you think.

Bill W5WVO


G4ILO wrote:

> Alan D. Wilcox wrote:
>>
>> Hello,
>> I gave away the feeble old PC I had by my radio equipment and
>> replaced it with a newer one ...
>>
>> Now I have S9+ noise wiping out 20 and 30 meters.
>>
>> Using same keyboard, mouse, monitor; just the PC in a new case.
>> Evidently it has a
>> noisy switcher supply in it. Tried 110V in-line filter, also
>> different 110V house circuit,
>> but still have noise. Grounds don't help. Don't happen to have a box
>> of toroids for chokes.
>>
> It's very likely to be the power supply, especially if it is a home
> build or a local PC store build rather than a branded model. Most of
> the PC cases and power supplies that home builders and small
> assemblers use are made in China, and the manufacturers often leave
> out all the components they can get away with, like anything to do
> with interference suppression. I remember someone a few years ago
> took apart a noisy power supply and could see all the holes in the PC
> board where the suppression components should have been. It was quite
> an eye opener.
>
> Replace it with a power supply from a decent manufacturer and all
> should be OK.
>
> -----
> Julian, G4ILO K2 s/n: 392  K3 s/n: ???
> G4ILO's Shack: www.g4ilo.com
> Zerobeat Ham Forums: www.zerobeat.net/smf

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[N5GE]

On Fri, 11 Jan 2008 10:03:27 -0500, W3DVX wrote:

>Hello,
>I gave away the feeble old PC I had by my radio equipment and replaced
>it with a newer one ...
>
>Now I have S9+ noise wiping out 20 and 30 meters.
>
>Using same keyboard, mouse, monitor; just the PC in a new case.
>Evidently it has a
>noisy switcher supply in it. Tried 110V in-line filter, also different
>110V house circuit,
>but still have noise. Grounds don't help. Don't happen to have a box of
>toroids for chokes.
>
>I've got an old PC supply or two in the junk box, but hoping something
>else might fix.

Does anyone have a sample recording of a switching power supply noise they could
post somewhere?

I don't use a switching power supply for running the rigs here, but I'm using a
new style dual core power supply in my computer.  Trouble is I don't know what
the switching noise sounds like.

Thanks,

Tom, N5GE - SWOT 3537 - Grid EM12jq

They that can give up essential liberty
to obtain a little temporary safety
deserve neither liberty nor safety.

http://www.n5ge.com
http://www.eQSL.cc/Member.cfm?N5GE

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[N2TK]

 I have had good luck replacing RF noisy PC power supplies with PC Power &
Cooling Supplies. They seem to be well filtered.
http://www.pcpower.com/index.html

By the way, something I did in my shack that significantly reduced noise
pickup:
- Any coax line that has to do with receiving I use 100% shielded RG6 with a
compression type F-connector. Where I didn't change to an F- female jack, I
use an F-adapter to PL-259 or 1/4" phono.
- Any coax line that has to do with transmitting I use 100% shielded
Buryflex.

It was amazing how much noise pickup dropped by getting rid of RG-213, RG-8X
and RG-58 in the shack.

N2TK, Tony

-----Original Message-----
From: [hidden email]
[mailto:[hidden email]] On Behalf Of Bill W5WVO
Sent: Friday, January 11, 2008 11:58 AM
To: [hidden email]
Subject: Re: [Elecraft] Computer Noise ruining 20 & 30m

One thing to be aware of -- and I too have had quite a bit of undesired
experience in this area -- hash from switching power supplies in computers
is
typically common mode noise, not differential noise. Consequently, a
differential line filter often won't knock it down very much, if at all.
What
you need is ferrite toroids -- big ones -- around and through which you wind

the power cord. In my case, the computer power supply is a 470W job in an
ATX
form factor, and because of the high power components, there wasn't any room

in the PS case for filtering! So the RF noise from this PS was horrendous.
It
took TWO large ferrite donuts in series, with the ENTIRE power cord wound
around them, to suppress the noise on 6M. I had bought a rather expensive
differential noise filter for the line, and it did absolutely nothing.
Brute-force common-mode filtering using ferrite toroids will usually cure
the
problem, but you may need a lot more saturability than you think.

Bill W5WVO


G4ILO wrote:

> Alan D. Wilcox wrote:
>>
>> Hello,
>> I gave away the feeble old PC I had by my radio equipment and
>> replaced it with a newer one ...
>>
>> Now I have S9+ noise wiping out 20 and 30 meters.
>>
>> Using same keyboard, mouse, monitor; just the PC in a new case.
>> Evidently it has a
>> noisy switcher supply in it. Tried 110V in-line filter, also
>> different 110V house circuit,
>> but still have noise. Grounds don't help. Don't happen to have a box
>> of toroids for chokes.
>>
> It's very likely to be the power supply, especially if it is a home
> build or a local PC store build rather than a branded model. Most of
> the PC cases and power supplies that home builders and small
> assemblers use are made in China, and the manufacturers often leave
> out all the components they can get away with, like anything to do
> with interference suppression. I remember someone a few years ago
> took apart a noisy power supply and could see all the holes in the PC
> board where the suppression components should have been. It was quite
> an eye opener.
>
> Replace it with a power supply from a decent manufacturer and all
> should be OK.
>
> -----
> Julian, G4ILO K2 s/n: 392  K3 s/n: ???
> G4ILO's Shack: www.g4ilo.com
> Zerobeat Ham Forums: www.zerobeat.net/smf

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[Phil Kane-2]

On Fri, 11 Jan 2008 13:20:39 -0500, N2TK wrote:

>I have had good luck replacing RF noisy PC power supplies with PC Power &
>Cooling Supplies. They seem to be well filtered.

  I use them in all three computers in the house.  No noise
  problems.

--
   73 de K2ASP - Phil Kane
   Elecraft K2/100   s/n 5402



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[Ed Gray W0SD]

Summary:
Based on the answers received and spending all morning reading on the
WEB it appears  PC Power and Cooling,  Startec and Antec at least at the
higher end have good computer power supplies. One amateur had good
success curing his problem with a Startech ATX POW450Pro, two reported
good results with PC Power and Cooling and one with Antec.  Other
possibility is Enermax but no testimonials.  A lot of the information is
in regards to a low DB noise level to the ear and delivering the power
without a voltage drop. and not much on  RFI/EMI information.  The ones
listed above do speak of RFI/EMI.   Be sure you buy the right power
supply for your computer.  They are not nearly as standard as they used
to be.

Thanks for some great input!

Ed W0SD


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[John Klewer]

Prior to buying my (ultra-quiet) Mac G5, I experienced a significant
amount of noise from my PC....doing a search with a handheld shortwave
radio in AM mode revealed it was primarily emanating from  the AC power
cable area.

Clip-on ferrite chokes on the power cable were completely ineffective.

I dismantled the computer, opened up the power supply and replaced the
power supply input connector (unfiltered) with a filtered one purchased
from Digi-key and the problem went away! Sorry, but I do not have the
part number...they are available from Digi-key, Mouser, Newark, etc, etc.

In the interest of maximizing profits the manufacturer omitted a
filtered input connector and let me instead buy it aftermarket.

John, N6AX






Alan D. Wilcox wrote:

> Hello,
> I gave away the feeble old PC I had by my radio equipment and replaced
> it with a newer one ...
>
> Now I have S9+ noise wiping out 20 and 30 meters.
>
> Using same keyboard, mouse, monitor; just the PC in a new case.
> Evidently it has a
> noisy switcher supply in it. Tried 110V in-line filter, also different
> 110V house circuit,
> but still have noise. Grounds don't help. Don't happen to have a box
> of toroids for chokes.
>
> I've got an old PC supply or two in the junk box, but hoping something
> else might fix.
>
> Any thoughts on an easy fix?
>
> Thanks,
> Alan
>
> Alan D. Wilcox, W3DVX
> 570-321-1516
> http://WilcoxEngineering.com
> Williamsport, PA 17701
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft   
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
>
>

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[Bill VanAlstyne W5WVO]

Great suggestion, Tony! A good way to tell if your RFI is being picked up by
leaky coax in the shack or by your beam is to rotate the beam. If the noise
changes amplitude during rotation, then at least some of it is being picked up
by your antenna, and the only solution is to eliminate the noise at its
source. This was the case in my situation, where my 6M stacked yagis are
fairly close to the shack (about 35 ft), but far enough to one side that the
directivity of the array had an effect.

Bill W5WVO


N2TK wrote:

> I have had good luck replacing RF noisy PC power supplies with PC
> Power & Cooling Supplies. They seem to be well filtered.
> http://www.pcpower.com/index.html
>
> By the way, something I did in my shack that significantly reduced
> noise pickup:
> - Any coax line that has to do with receiving I use 100% shielded RG6
> with a compression type F-connector. Where I didn't change to an F-
> female jack, I use an F-adapter to PL-259 or 1/4" phono.
> - Any coax line that has to do with transmitting I use 100% shielded
> Buryflex.
>
> It was amazing how much noise pickup dropped by getting rid of
> RG-213, RG-8X and RG-58 in the shack.
>
> N2TK, Tony
>
> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of Bill W5WVO
> Sent: Friday, January 11, 2008 11:58 AM
> To: [hidden email]
> Subject: Re: [Elecraft] Computer Noise ruining 20 & 30m
>
> One thing to be aware of -- and I too have had quite a bit of
> undesired experience in this area -- hash from switching power
> supplies in computers is
> typically common mode noise, not differential noise. Consequently, a
> differential line filter often won't knock it down very much, if at
> all. What
> you need is ferrite toroids -- big ones -- around and through which
> you wind
>
> the power cord. In my case, the computer power supply is a 470W job
> in an ATX
> form factor, and because of the high power components, there wasn't
> any room
>
> in the PS case for filtering! So the RF noise from this PS was
> horrendous. It
> took TWO large ferrite donuts in series, with the ENTIRE power cord
> wound around them, to suppress the noise on 6M. I had bought a rather
> expensive differential noise filter for the line, and it did
> absolutely nothing. Brute-force common-mode filtering using ferrite
> toroids will usually cure the
> problem, but you may need a lot more saturability than you think.
>
> Bill W5WVO
>
>
> G4ILO wrote:
>> Alan D. Wilcox wrote:
>>>
>>> Hello,
>>> I gave away the feeble old PC I had by my radio equipment and
>>> replaced it with a newer one ...
>>>
>>> Now I have S9+ noise wiping out 20 and 30 meters.
>>>
>>> Using same keyboard, mouse, monitor; just the PC in a new case.
>>> Evidently it has a
>>> noisy switcher supply in it. Tried 110V in-line filter, also
>>> different 110V house circuit,
>>> but still have noise. Grounds don't help. Don't happen to have a box
>>> of toroids for chokes.
>>>
>> It's very likely to be the power supply, especially if it is a home
>> build or a local PC store build rather than a branded model. Most of
>> the PC cases and power supplies that home builders and small
>> assemblers use are made in China, and the manufacturers often leave
>> out all the components they can get away with, like anything to do
>> with interference suppression. I remember someone a few years ago
>> took apart a noisy power supply and could see all the holes in the PC
>> board where the suppression components should have been. It was quite
>> an eye opener.
>>
>> Replace it with a power supply from a decent manufacturer and all
>> should be OK.
>>
>> -----
>> Julian, G4ILO K2 s/n: 392  K3 s/n: ???
>> G4ILO's Shack: www.g4ilo.com
>> Zerobeat Ham Forums: www.zerobeat.net/smf
>
> _______________________________________________
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>
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[Bill VanAlstyne W5WVO]

Yup. Lower wattage supply uses smaller componets which allows the inclusion of
filter components (presumably due to more room in chassis space and components
budget). It's a hypothetical model, as I've never taken one of these "big
boys" apart, but I've seen going to a lower-power supply fix this kind of
noise problem more than once. Of course, don't go to a PS that puts out less
power than your computer needs.  :-)

I saw in another post in this thread that Antec was said to be a power supply
one could count on to be less noisy. I think it has a lot more to do with the
power rating than with the brand. The PS I had that was putting out so much
noise was an Antec, the biggest one they made. I'm still using it, but it is
brute-force choked up the yin-yang.

Bill W5WVO


Alan D. Wilcox wrote:

> SOLVED!
> Just replaced the 400w supply with a 300w that I had in the junk box.
> Both foreign cheap
> units, but that's all the local PC shops seem to carry (at least at my
> QTH). The replacement
> is nicely quiet ... and a lot easier fix than what I was dreading!
>
> Now that I can hear the radio properly, back to doing the remote audio
> with HRD.
>
> Thanks for the help!
> Alan
> ------------------------------------------------------------------------
>
> Alan D. Wilcox wrote:
>> Hello,
>> I gave away the feeble old PC I had by my radio equipment and
>> replaced it with a newer one ...
>>
>> Now I have S9+ noise wiping out 20 and 30 meters.
>>
>> Using same keyboard, mouse, monitor; just the PC in a new case.
>> Evidently it has a
>> noisy switcher supply in it. Tried 110V in-line filter, also
>> different 110V house circuit,
>> but still have noise. Grounds don't help. Don't happen to have a box
>> of toroids for chokes.
>>
>> I've got an old PC supply or two in the junk box, but hoping
>> something else might fix.
>>
>> Any thoughts on an easy fix?
>>
>> Thanks,
>> Alan
>>
>> Alan D. Wilcox, W3DVX
>> 570-321-1516
>> http://WilcoxEngineering.com
>> Williamsport, PA 17701
>
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[Matthew D. Fuller-2]

On Fri, Jan 11, 2008 at 10:32:50AM -0800 I heard the voice of
Phil Kane, and lo! it spake thus:
> On Fri, 11 Jan 2008 13:20:39 -0500, N2TK wrote:
>
> >I have had good luck replacing RF noisy PC power supplies with PC
> >Power & Cooling Supplies. They seem to be well filtered.
>
>   I use them in all three computers in the house.  No noise
>   problems.

I third the motion.  And aside from the RF issues, they're really
really well-built power supplies.  Lots of very clean output; not
over-rated like a lot of power supplies are.  Good components
(electrical and mechanical) so they last a long time.  The Silencer
series are impressively quiet.  And good workmanship; last one I put
in a system, I took apart first (hey, it's a habit ;) and was pleased
with the cleanliness and precision of the assembly.


--
Matthew Fuller, N3TZJ
<[hidden email]>
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[Bill W4ZV]

John Klewer wrote

I dismantled the computer, opened up the power supply and replaced the
power supply input connector (unfiltered) with a filtered one purchased
from Digi-key and the problem went away! Sorry, but I do not have the
part number...they are available from Digi-key, Mouser, Newark, etc, etc.

Corcom 6EF1 is what you want.  About $10 in single units (about half that on eBay for 5 units).  This problem has been around for over 10 years but the manufacturers keep shipping junk.

http://lists.contesting.com/archives//html/RFI/1998-05/msg00018.html

73,  Bill  W4ZV

[Justin Croonenberghs-2]

On Fri, 2008-01-11 at 13:20 -0500, N2TK wrote:
> I have had good luck replacing RF noisy PC power supplies with PC Power &
> Cooling Supplies. They seem to be well filtered.
> http://www.pcpower.com/index.html

I've had fairly good luck with Antec power supplies when dealing with my
other electronics projects. It's been a while since I've purchased one,
though.

http://www.antec.com/

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