On 7/4/2012 9:10 AM, Bill Cromwell wrote: > 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 > Hi Bill!!
Just for reference, my HP generates NO noise. It is possible to get clean supplies, although I can't tell you what is in this box. This was purchased as a complete unit and came through a government purchasing source available to employees. You might also want to try a UPS between the computer and the line. I have had that help me in a couple of cases. -- Kim Herron W8ZV 1-616-677-3706 _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK