K3 & flatscreen monitor noise - solved
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My flatscreen, by the way, is an inexpensive LG.
It was suggested that the garbage is likely from the switcher supply within the flatscreen monitor. I put the monitor on an ICE AC powerline filter, and 99% of the noise went away, the worst of it is now well down. That's much better! Still. I'll bet that there are monitors out there that are clean along with many which are not. some folks who have monitors that are by themselves clean, might offer the model to the list. 73, Fred - kt5x K2 # 0700 K3 # 0144 www.KT5X.com ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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I have an Acer X223W, about $170 from Walmart which seems fine. No interference
that I have identified and the monitor looks great except for one corner where my sneeze got it. Willis 'Cookie' Cooke K5EWJ ________________________________ From: Fred Maas <[hidden email]> To: [hidden email] Sent: Sun, September 5, 2010 12:48:48 PM Subject: [Elecraft] K3 & flatscreen monitor noise - solved My flatscreen, by the way, is an inexpensive LG. It was suggested that the garbage is likely from the switcher supply within the flatscreen monitor. I put the monitor on an ICE AC powerline filter, and 99% of the noise went away, the worst of it is now well down. That's much better! Still. I'll bet that there are monitors out there that are clean along with many which are not. some folks who have monitors that are by themselves clean, might offer the model to the list. 73, Fred - kt5x K2 # 0700 K3 # 0144 www.KT5X.com ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: K3 & flatscreen monitor noise - solved
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In reply to this post by Fred Maas
My Sony TFT LCD Model SDM-S51 is totally "quiet" setting beside my K3, and there is also a 1000 channel scanner in the shack that doesn't hear anything from the monitor. 73! Ken Kopp - K0PP [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: K3 & flatscreen monitor noise - solved
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In reply to this post by Fred Maas
HP 2709m (27" LCD), which sits literally on top of my K3, is 100% quiet.
This monitor is absolutely without broadband noise emission at any frequency I have used, HF-VHF. I haven't gone so far as to scan it with a SA, because I don't have one, but nothing I can detect actually using it while on the air. Really love this monitor, BTW. I'd put in a second one if I could afford it. Exceptionally clear and bright, driving it with DVI. Can also drive it with analog VGA and HDMI, neither of which I've tried. CNET gave it a "GOOD" three-star rating, while user reviews were somewhat more generous (four stars). Bill W5WVO -------------------------------------------------- From: "Fred Maas" <[hidden email]> Sent: Sunday, September 05, 2010 17:48 To: <[hidden email]> Subject: [Elecraft] K3 & flatscreen monitor noise - solved > My flatscreen, by the way, is an inexpensive LG. > > It was suggested that the garbage is likely from the switcher supply > within the flatscreen monitor. > > I put the monitor on an ICE AC powerline filter, and 99% of the noise went > away, the worst of it is now well down. That's much better! > > Still. I'll bet that there are monitors out there that are clean along > with many which are not. some folks who have monitors that are by > themselves clean, might offer the model to the list. > > 73, Fred - kt5x > > K2 # 0700 > > K3 # 0144 > > www.KT5X.com > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: K3 & flatscreen monitor noise - solved
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> This monitor is absolutely without broadband noise emission at any
> frequency... Be careful when assessing noise from shack and household appliances. I have had devices that raised the noise floor by several dB across the spectrum of the band. The noise was so evenly broad that movement in frequency resulted in no change of the noise floor. My own noise mitigation plan includes establishing a reference baseline on all bands using an SDR-IQ as a panadapter with the K3. I first cut power to the entire house, including removal of power to battery-backed devices like the home security system. With the SDR-IQ, screen captures can be saved and archived for later reference. After the initial baseline is recorded, I then apply power to all home devices, again taking screen captures of the bands. Then, one-by-one, I kill power to the breaker panel circuits, identifying noisy circuits. Next, devices on the circuit are found. Finally, noisy devices are worked through the addition of ferrite and CORCOM type CM chokes, replacement of switch-mode supplies with linear supplies, and in some tough cases, complete appliance replacement has been necessary. In the past year, I've either modified or replaced over a dozen devices, most of which are small switch-mode wall warts that power my Netgear LAN equipment. A few days ago I autopsied one of the Netgear wall-wart supplies. There's absolutely no EMI/RFI abatement anywhere in the circuit. The noise floor will be affected by shielding integrity of the rig and shack cabling as well as the type of transmission line used. Folks bringing in balanced feeders to a tuner in the shack are probably most susceptible to home-generated noise sources. I am using homebrewed 600-ohm line to a motorized balanced ATU outside the house. CM chokes are used on the coaxial line portion, but a good bit of interference is being coupled onto the 600-ohm line. As line spacing increases, losses are minimized but noise ingress is inversely proportional to the benefit attained with lower line loss. With the proliferation of SDR receivers, the LP-PAN unit and now the P3, it's easier than ever to identify and resolve noise problems within your own home. Outside the boundaries of your property, more complex DF measurement methods must be used, but its all manageable with good technique and patience. Paul, W9AC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
Re: K3 & flatscreen monitor noise - solved
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In reply to this post by Fred Maas
Fred Maas wrote:
> Still. I'll bet that there are monitors out there that are clean along with many which are not. some folks who have monitors that are by themselves clean, might offer the model to the list. It is plasma displays that tend to have the serious RFI problems. -- David Woolley "we do not overly restrict the subject matter on the list, and we encourage postings on a wide range of amateur radio related topics" List Guidelines <http://www.elecraft.com/elecraft_list_guidelines.htm> ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html |
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