Owen, Unless I'm reading the waterfall spectrum frequency scale incorrectly, the line spacing you see on 80M is suspiciously close to 60 Hz. Do you observe this same interference line spacing across the 80M band, or only in the vicinity of 3580 kHz? The audio file sounds like the noise I experience here in the northeast U.S. during much of the year, except immediately after a strong rainstorm, which suggests an arc source on the nearby utility distribution system in my own situation -- your source(s) may be different. While there are many possible methods of 60 Hz power line interference coupling into your setup, most involve some form of common-mode coupling. A good tutorial on this issue is Jim, K9YC's article, which has been frequently cited in this forum: http://www.audiosystemsgroup.com/RFI-Ham.pdf . Another widely cited article is that by Chuck, W1HIS:
http://www.yccc.org/Articles/W1HIS/CommonModeChokesW1HIS2006Apr06.pdf . Others have weighed in on the feasibility of attenuating the interference with DSP, but I would start by trying to eliminate possible sources of 60 Hz noise within your own household. Try running your K2 from a battery source while turning off individual power circuits at your breaker panel (if accessible to you), and see if the noise disappears. Of course it's essential to enlist the support of other members of the household before you begin turning off their favorite gadgets! The interference sources may well be outside your own apartment, yet within your building, in which case greater diplomatic skill is required. Your 40M noise source sounds qualitatively different to me from that on 80M, and the waterfall spectrum display is obviously different from that you observed on 80M. It would appear that you may be dealing with at least two different sources of interference. 73, and good luck! Mike, K8CN -- View this message in context: http://elecraft.365791.n2.nabble.com/Will-the-K2-noise-blanker-help-with-this-QRM-tp5864463p5871947.html Sent from the [K2] mailing list archive at Nabble.com. ______________________________________________________________ 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
