Hi I suggest checking if there is good electrical contact between the metal casing of the PC power supply unit (PSU) and the computer metal case itself - scratch off the case painting under screws keeping both of them together to provide better contact. I had terrible RFI from my freshly assembled shack PC this August. And while experimenting with extra grounding it to get rid of RFI, for my surprise I discovered that noise goes away by ~95% when I mess with case screws. Then I scratched the case painting off below the screws and noise was almost gone. I assume if it would be in neighbors house, I wouldn't feel it anymore then. However, there still were some weak RFI birdies here and there (60 Hz spacing approx), and as it was meant to be my HAM shack PC, I could not live with idea that I add extra noise on top of existing neighbor's crap. So I just replaced the PSU to another one I got for free after asking friends around, and luckily no more RFI issues from this PC.
The RFI generating PSU was brand-new "Be Quiet! System Power 9 500W" (I find the name ironical for a PSU generating RFI). The good one had Chieftec label. Both of them are kind of "made in China, quality controlled in Germany". 73! Agris/YL2VW On Tue, 26 Nov 2019 at 13:49, Rodman, David <[email protected]> wrote: > A few ideas might be helpful here. I was at the station over the weekend > and found a significant amount of noise coming from one of two computers in > the station. Significant noise S5 at 1820. One computer runs the cluster > and 2m connection. That was clean. The other handles most of the remote > chores and has about 15 USB serial devices attached. Everything was off, > except a battery operated transceiver attached to the receive antenna feed, > the modem for the cable and my router. One can definitely see that > operating the computer, closing windows or plugging in USB devices causes > the modulation on the signal to change, this isolating the source to the > computer alone and possible connections to peripherals (they were all > turned off by the way). I did have few chokes available but attaching them > to the USB wires out of the computer to their various devices made no > improvement. I could get more specific but need to leave for my office > now. Any ideas might be helpful and appreciat > ed. > > > --- > David J Rodman MD > Assistant Clinical Professor > Department of Ophthalmology > SUNY/Buffalo > > Office 716-857-8654 > _________________ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
