Re: Topband: Progress with ugly computer noise
Unless there is something unusual about the existing power supply you could consider replacing the supply with something like a good Antec or Cooler Master unit. Online prices for 500W supplies are $50-$60. This assumes that you are certain the noise is coming from the power supply. I have never heard a peep from either of the brands mentioned above. - Wes Attaway (N5WA) --- 1138 Waters Edge Circle, Shreveport, LA 71106 318-797-4972 (Office) - 318-393-3289 (Cell) Computer Consulting and Forensics -- EnCase Certified Examiner --- -Original Message- From: topband-boun...@contesting.com [mailto:topband-boun...@contesting.com] On Behalf Of Jim Brown Sent: Wednesday, July 04, 2012 11:14 AM To: topband@contesting.com Subject: Re: Topband: Progress with ugly computer noise On 7/4/2012 6:10 AM, Bill Cromwell wrote: Next I'll be getting my hands on some ferrite core materials and looking to see just how far I can reduce the noise. When faced with a noisy computer, the first thing I'd try (other than replacing the noisy supply) would be a multi-turn choke on the power cable, optimized (number of turns and core) for the band(s) where you're hearing the most noise. If noise remained, I'd next tackle the video cable and the printer cable. Use the graphs in Appendix One of http://audiosystemsgroup.com/RFI-Ham.pdf as a guide to picking the cores and winding the chokes. Do your fellow hams another favor -- post the brand names and/or vendors of both the noisy power supply and the one that fixed your problem (if it does). :) 73, Jim K9YC ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Progress with ugly computer noise
That sounds like the power supply is missing the usual common-mode input filter that switching power supplies nearly always have. There are companies like corcom that make emi filters for the line. Some of these filters are integrated with the IEC power connector for the power cord. If your power supply has enough space to fit one of the combo filter/connectors in place of the stock connector that might help -- even with your new supply. This would put the filtering inside the computer chassis which would likely be better than anything you could put on the power cord alone. -Bill [Sent using Blackberry Messaging] - Original Message - From: topband-boun...@contesting.com topband-boun...@contesting.com To: topband@contesting.com topband@contesting.com Sent: Wed Jul 04 09:10:39 2012 Subject: Topband: Progress with ugly computer noise Hi, I have been limping along with a really ugly replacement power supply in my big computer. It's networked (think of internet tools). I could hear *nothing* on my radios aside from the racket made by that power supply. I even found my power supply listed on the internet as an example of *ugly*. There is no EMI filter at all - just two jumpers where the filter is supposed to be. The computer had to be turned off to even think of using a radio. I have paid for a new, better quality power supply (only $2 more) and the online tracker suggests it will be in my mailbox any minute..maybe tomorrow. I got impatient. I have two of those ugly supplies so I took the filter parts out of one of the dead ones and installed them in this one. I put the supply in the computer and it made quite a difference! It's not good enough yet but I am listening to hams on 40 meters while I am typing this! I couldn't do that before. Next I'll be getting my hands on some ferrite core materials and looking to see just how far I can reduce the noise. I have two laptop computers here, older and newer, and I can barely tell when I turn either of them on. Neither one talks to my network at the moment so I will have to correct that. But I have a target noise performance for my PC tower, now. Meanwhile I have the noise knocked down well enough to try using this computer to help with operations while on the air. I may be unable to hear the weakest signals but I'll see how that goes. 73, Bill KU8H ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Progress with ugly computer noise
On Wed, 2012-07-04 at 09:14 -0700, Jim Brown wrote: On 7/4/2012 6:10 AM, Bill Cromwell wrote: Next I'll be getting my hands on some ferrite core materials and looking to see just how far I can reduce the noise. When faced with a noisy computer, the first thing I'd try (other than replacing the noisy supply) would be a multi-turn choke on the power cable, optimized (number of turns and core) for the band(s) where you're hearing the most noise. If noise remained, I'd next tackle the video cable and the printer cable. Use the graphs in Appendix One of http://audiosystemsgroup.com/RFI-Ham.pdf as a guide to picking the cores and winding the chokes. Do your fellow hams another favor -- post the brand names and/or vendors of both the noisy power supply and the one that fixed your problem (if it does). :) 73, Jim K9YC Hi Jim, This PC did not produce any interference before I replaced the power supply. That tells me I shouldn't expect any interference from any of the parts that were in use before. I'll post the information about the power supplies. In fact the evil one has a Circled A logo and is named named Vista and is a 500 watt, dual fan, ATX power supply. I have two. The one that's online has been modified with a partial EMI filter. One has not been modified at all. Both were equally bad before the mods. I'll look at Mouser to see what kind of modular filter might be available to solder in where I have removed the jumpers. A quick scan showed that those are not terribly expensive. Now I have made physical measurements of the filter space and circuit board pads I can take a closer look to see what will fit. The internal EMI filter is right at the power cord connector. The partial filter I installed has already had a remarkable effect. Another tower I have here was using one of the new supplies to wipe out my radio operations. I put an old, lower capacity supply into that one and it quieted right back down. This one needs more steam so I can't put my old 300 watt supply in and expect it to survive for very long. In fact, guess how I killed the original power supply (hanging my head in shame). I expect things to just keep getting better :) 73, Bill KU8H ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Progress with ugly computer noise
Ditto on the Antec, Ive been using them on both the higher end PC's Ive built for several years and I dont have to keep upgrading as I change or add things. Very cool running too. Carl KM1H - Original Message - From: Wes Attaway (N5WA) wesatta...@bellsouth.net To: j...@audiosystemsgroup.com; topband@contesting.com Sent: Wednesday, July 04, 2012 12:42 PM Subject: Re: Topband: Progress with ugly computer noise Unless there is something unusual about the existing power supply you could consider replacing the supply with something like a good Antec or Cooler Master unit. Online prices for 500W supplies are $50-$60. This assumes that you are certain the noise is coming from the power supply. I have never heard a peep from either of the brands mentioned above. - Wes Attaway (N5WA) --- 1138 Waters Edge Circle, Shreveport, LA 71106 318-797-4972 (Office) - 318-393-3289 (Cell) Computer Consulting and Forensics -- EnCase Certified Examiner --- -Original Message- From: topband-boun...@contesting.com [mailto:topband-boun...@contesting.com] On Behalf Of Jim Brown Sent: Wednesday, July 04, 2012 11:14 AM To: topband@contesting.com Subject: Re: Topband: Progress with ugly computer noise On 7/4/2012 6:10 AM, Bill Cromwell wrote: Next I'll be getting my hands on some ferrite core materials and looking to see just how far I can reduce the noise. When faced with a noisy computer, the first thing I'd try (other than replacing the noisy supply) would be a multi-turn choke on the power cable, optimized (number of turns and core) for the band(s) where you're hearing the most noise. If noise remained, I'd next tackle the video cable and the printer cable. Use the graphs in Appendix One of http://audiosystemsgroup.com/RFI-Ham.pdf as a guide to picking the cores and winding the chokes. Do your fellow hams another favor -- post the brand names and/or vendors of both the noisy power supply and the one that fixed your problem (if it does). :) 73, Jim K9YC ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1424 / Virus Database: 2437/5110 - Release Date: 07/04/12 ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Progress with ugly computer noise
I will also echo the comments on the Antec power supplies. Used one as a replacement a couple of years ago and the computer noise is gone. Mike WA5POK -Original Message- From: ZR Sent: Wednesday, July 04, 2012 11:59 AM To: Wes Attaway (N5WA) ; j...@audiosystemsgroup.com ; topband@contesting.com Subject: Re: Topband: Progress with ugly computer noise Ditto on the Antec, Ive been using them on both the higher end PC's Ive built for several years and I dont have to keep upgrading as I change or add things. Very cool running too. Carl KM1H - Original Message - From: Wes Attaway (N5WA) wesatta...@bellsouth.net To: j...@audiosystemsgroup.com; topband@contesting.com Sent: Wednesday, July 04, 2012 12:42 PM Subject: Re: Topband: Progress with ugly computer noise Unless there is something unusual about the existing power supply you could consider replacing the supply with something like a good Antec or Cooler Master unit. Online prices for 500W supplies are $50-$60. This assumes that you are certain the noise is coming from the power supply. I have never heard a peep from either of the brands mentioned above. - Wes Attaway (N5WA) --- 1138 Waters Edge Circle, Shreveport, LA 71106 318-797-4972 (Office) - 318-393-3289 (Cell) Computer Consulting and Forensics -- EnCase Certified Examiner --- -Original Message- From: topband-boun...@contesting.com [mailto:topband-boun...@contesting.com] On Behalf Of Jim Brown Sent: Wednesday, July 04, 2012 11:14 AM To: topband@contesting.com Subject: Re: Topband: Progress with ugly computer noise On 7/4/2012 6:10 AM, Bill Cromwell wrote: Next I'll be getting my hands on some ferrite core materials and looking to see just how far I can reduce the noise. When faced with a noisy computer, the first thing I'd try (other than replacing the noisy supply) would be a multi-turn choke on the power cable, optimized (number of turns and core) for the band(s) where you're hearing the most noise. If noise remained, I'd next tackle the video cable and the printer cable. Use the graphs in Appendix One of http://audiosystemsgroup.com/RFI-Ham.pdf as a guide to picking the cores and winding the chokes. Do your fellow hams another favor -- post the brand names and/or vendors of both the noisy power supply and the one that fixed your problem (if it does). :) 73, Jim K9YC ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1424 / Virus Database: 2437/5110 - Release Date: 07/04/12 ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Progress with ugly computer noise
There are at least five different OEM manufacturers for the brand name ANTEC. Read this article about power supplies and how to identify the manufacturer by the UL code listed on the supply. http://www.tomshardware.com/reviews/power-supply-oem-manufacturer,2913.html A very good tutorial IMHO. Tom K6VCR -Original Message- From: topband-boun...@contesting.com [mailto:topband-boun...@contesting.com] On Behalf Of ZR Sent: Wednesday, July 04, 2012 9:59 AM To: Wes Attaway (N5WA); j...@audiosystemsgroup.com; topband@contesting.com Subject: Re: Topband: Progress with ugly computer noise Ditto on the Antec, Ive been using them on both the higher end PC's Ive built for several years and I dont have to keep upgrading as I change or add things. Very cool running too. Carl KM1H - Original Message - From: Wes Attaway (N5WA) wesatta...@bellsouth.net To: j...@audiosystemsgroup.com; topband@contesting.com Sent: Wednesday, July 04, 2012 12:42 PM Subject: Re: Topband: Progress with ugly computer noise Unless there is something unusual about the existing power supply you could consider replacing the supply with something like a good Antec or Cooler Master unit. Online prices for 500W supplies are $50-$60. This assumes that you are certain the noise is coming from the power supply. I have never heard a peep from either of the brands mentioned above. - Wes Attaway (N5WA) --- 1138 Waters Edge Circle, Shreveport, LA 71106 318-797-4972 (Office) - 318-393-3289 (Cell) Computer Consulting and Forensics -- EnCase Certified Examiner --- -Original Message- From: topband-boun...@contesting.com [mailto:topband-boun...@contesting.com] On Behalf Of Jim Brown Sent: Wednesday, July 04, 2012 11:14 AM To: topband@contesting.com Subject: Re: Topband: Progress with ugly computer noise On 7/4/2012 6:10 AM, Bill Cromwell wrote: Next I'll be getting my hands on some ferrite core materials and looking to see just how far I can reduce the noise. When faced with a noisy computer, the first thing I'd try (other than replacing the noisy supply) would be a multi-turn choke on the power cable, optimized (number of turns and core) for the band(s) where you're hearing the most noise. If noise remained, I'd next tackle the video cable and the printer cable. Use the graphs in Appendix One of http://audiosystemsgroup.com/RFI-Ham.pdf as a guide to picking the cores and winding the chokes. Do your fellow hams another favor -- post the brand names and/or vendors of both the noisy power supply and the one that fixed your problem (if it does). :) 73, Jim K9YC ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1424 / Virus Database: 2437/5110 - Release Date: 07/04/12 ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Progress with ugly computer noise
According to the schematic on the side, it consists of 2 x 2.5 mH indutors, one in series with each leg, a 2200 pF cap shunting the line input and 0.1uF capacitors from each leg to ground on the load side. It's generally two inductors wound on a single core for common-mode choking. The result is that total common-mode inductance is 2*L while differential-mode inductance cancels and equals zero. The 2200pF caps are differential-mode shunts to ground. Some of these modules can be purchased with complex combinations of both common-mode and differential-mode inductance and capacitance sections. I use them for almost all home-brewed projects that require an AC supply. Paul, W9AC ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Progress with ugly computer noise
FB - that explains the semi-circular arrow between the two inductors on the schematic - I wasn't familiar with the notation. I don't know the whys and wherefores, so I just picked the most elaborate of the several filters they showed on the catalog page - as I recall, it cost around $10 plus shipping, so I got two while I was at it. 73, Pete N4ZR The World Contest Station Database, at www.conteststations.com The Reverse Beacon Network at http://reversebeacon.net, blog at reversebeacon.blogspot.com, spots at telnet.reversebeacon.net, port 7000 and arcluster.reversebeacon.net, port 7000 On 7/4/2012 3:41 PM, Paul Christensen wrote: According to the schematic on the side, it consists of 2 x 2.5 mH indutors, one in series with each leg, a 2200 pF cap shunting the line input and 0.1uF capacitors from each leg to ground on the load side. It's generally two inductors wound on a single core for common-mode choking. The result is that total common-mode inductance is 2*L while differential-mode inductance cancels and equals zero. The 2200pF caps are differential-mode shunts to ground. Some of these modules can be purchased with complex combinations of both common-mode and differential-mode inductance and capacitance sections. I use them for almost all home-brewed projects that require an AC supply. Paul, W9AC ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Progress with ugly computer noise
It's generally two inductors wound on a single core for common-mode choking. The result is that total common-mode inductance is 2*L while differential-mode inductance cancels and equals zero. Total common mode inductance is 1 times L, not two times L. This is because the windings are parallel with near infinite mutual coupling. It is exactly like a bifilar filament choke. The 2200pF caps are differential-mode shunts to ground. Some of these modules can be purchased with complex combinations of both common-mode and differential-mode inductance and capacitance sections. I use them for almost all home-brewed projects that require an AC supply. It's far more effective to use two isolated inductors, provided the current drawn by the supply does not saturate the inductors. The main reason for bifilar or dual parallel windings is current from the supply does not bias the core. The problem is, it has almost no differential mode impedance. It's a far more effective filter, if the cores are isolated, because it will remove common just as well and have much more differential rejection on mains lines. I think a computer about two miles from me set the all time record for distance. That computer was driving the Telco lines via the modem and power lines in differential, so the Telco and power acted like a big open wire line. It went for miles along the road with very little attenuation. I gave them a surge suppressor / protector with terminals for Telco and outlets. The Telco and safety ground were already bypassed together with gas protection tubes and small bypass caps. I added .01uF UL/CSA/VDE approved line caps from the neutral and hot to safety at the outlet feedpoint. I added isolated chokes for each wire, none bifilar, with a string of low-Q beads. Cleaned it up so much the computer could not be heard right in the same room. I did the same with a Direct TV recorder next door. It drove the mains in differential mode with significant energy. 73 Tom ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Progress with ugly computer noise
A lot, probably most, of the really cheap UPSes are just switching step-up converters. The easy way to spot them is from the crazy ratings like 1000va but only 3 amps (which should be about 360va). They sell them based on people thinking bigger is better even though a .36 power factor is pretty useless. I used to always think apc's .7 was misleading... The big commercial units are .8-.9. I've personally always had good luck with the apc smartUPS line for small upses. They are sinewave output (and surprisingly good when checked w/ a scope), and pretty clean due primarily to their pseudo-ferroresonant design. I'd stay away from the backUPS line though since those aren't much different from the el-cheapo units. Note that supposedly bad smartUPS upses can be found for cheap at swaps and on ebay. Almost always all that is needed is a new set of batteries to get them running again. -Bill [Sent using Blackberry Messaging] - Original Message - From: topband-boun...@contesting.com topband-boun...@contesting.com To: TOPBAND TOPBAND@CONTESTING.COM Sent: Wed Jul 04 18:14:07 2012 Subject: Topband: Progress with ugly computer noise Be careful with UPS units as I have seen them cause more problems noise wise that computers. A friend of mine had a really bad one he had to unplug to operate on any band. Everything was clean once he got rid of that thing.. 73 Mike K4PI ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Progress with ugly computer noise
So much for part 15. -Original Message- From: topband-boun...@contesting.com [mailto:topband-boun...@contesting.com] On Behalf Of Bill Wichers Sent: Wednesday, July 04, 2012 6:34 PM To: k...@bellsouth.net; TOPBAND@CONTESTING.COM Subject: Re: Topband: Progress with ugly computer noise A lot, probably most, of the really cheap UPSes are just switching step-up converters. The easy way to spot them is from the crazy ratings like 1000va but only 3 amps (which should be about 360va). They sell them based on people thinking bigger is better even though a .36 power factor is pretty useless. I used to always think apc's .7 was misleading... The big commercial units are .8-.9. I've personally always had good luck with the apc smartUPS line for small upses. They are sinewave output (and surprisingly good when checked w/ a scope), and pretty clean due primarily to their pseudo-ferroresonant design. I'd stay away from the backUPS line though since those aren't much different from the el-cheapo units. Note that supposedly bad smartUPS upses can be found for cheap at swaps and on ebay. Almost always all that is needed is a new set of batteries to get them running again. -Bill [Sent using Blackberry Messaging] - Original Message - From: topband-boun...@contesting.com topband-boun...@contesting.com To: TOPBAND TOPBAND@CONTESTING.COM Sent: Wed Jul 04 18:14:07 2012 Subject: Topband: Progress with ugly computer noise Be careful with UPS units as I have seen them cause more problems noise wise that computers. A friend of mine had a really bad one he had to unplug to operate on any band. Everything was clean once he got rid of that thing.. 73 Mike K4PI ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Progress with ugly computer noise
On Wed, 2012-07-04 at 15:41 -0400, Paul Christensen wrote: According to the schematic on the side, it consists of 2 x 2.5 mH indutors, one in series with each leg, a 2200 pF cap shunting the line input and 0.1uF capacitors from each leg to ground on the load side. ---snip--- Paul, W9AC I found a similar circuit and copied that into my power supply. Now I can't hear it in the radio. I'm pumped grin. $10 for the modular units seems pretty reasonable to me. I'll be looking at those for future problems a dn Have made notes about various brands. The one I ordered (and still not here) also had glowing recommendations. I'll report results for that one when I get it. I have been avoiding running my backup srver (backs up personal data for the family's computers) because the power supply is on the light weight side. But it's quiet. 73, Bill KU8H ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
