May I encourage everyone to study the excellent work from Jim Brown, K9YC — he weighed in here and you’ll see his link below. I’m also taking his suggestion after careful study to replace the parallel zip line red-black cable with shielded twisted pair cable (18 AWG ) with the Anderson Power Poles connectors. The theory being that anything twisted will resist RFI while parallel cable invites it and generates it. A fist full of ferrites helps also. Getting surgical, but it really helps.
David A., KK6DA > On Apr 11, 2016, at 6:29 AM, Myron Schaffer <[email protected]> wrote: > > One thing I have noticed over the years is that the near-field noise is > present with most any modern electronics. The switching frequency is between > 200-300kHz and can be easily sniffed with a pocket AM radio (harmonics of > that fundamental switching frequency are easily spotted with an AM radio). > When I bring my CCrane Pocket Radio in the near field at the operating > position, I can’t tune in the semi-local 600 KCOL out of Greely, CO. If I > back up a few feet the noise level drops considerably and the station is > audible again. The CC Pocket Radio has a fairly good front end with somewhat > good selectivity but is still overloaded with IBOC noise. > > I have battery chargers, an old Dell 1501 laptop, an external HD with > switcher, the list goes on. Common mode noise and strong near-field noise is > the bane of my ham radio existence in this RFI rich environment. > > Myron WV0H > Printed on Recycled Data > > From: Jim Brown > Sent: Monday, April 11, 2016 12:14 AM > To: [email protected] > Subject: Re: [Elecraft] RFI resistant Monitor > > On Sun,4/10/2016 10:44 PM, KC6CNN wrote: >> I just found that when the monitor is on it adds 2 bars of noise to my >> meter. It is also turning off when I operate on certain bands. > > I had exactly that experience with a Samsung that W4UAT gave me because > it did that in his shack too. It also makes RF noise. The good news is > that not all Samsung monitors are RFI dogs. I have two recent model > Samsungs in my house and four in the shack. They are designed to run on > power supplies labeled 14VDC, and the supply they sell you is a > switching power supply that makes RF noise. I throw those power supplies > away, cut the attached power cable and attach red/black PowePoles, and > run them from either the 12V battery system in my shack or a small 12V > lead-acid cell that I float-charge from a linear 12V wall wart. > > I also use ferrite common mode chokes on both the video cable that runs > to the computer and the power supply cable "just in case" some RF trash > is conducted to those cables, which the cables could radiate. > > All that, and a lot more, is discussed in this "in progress" article for > the National Contest Journal. k9yc.com/KillingReceiveNoise.pdf > > 73, Jim K9YC > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [email protected] > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[email protected] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [email protected] David Ahrendts [email protected] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
