One of the items that many overlook is in-freezer ice makers. They can make a lot of broadband noise when the heater is running. Yes - heater. Once the ice cubes are frozen they need to be ejected. In order to do this smoothly, the "tray" is heated up just enough to let the cubes pop loose. The heaters I've seen (and heard) use a type of PWM applied to a heating element, and the PWM creates broadband RFI. The heater is usually on for 1-2 minutes, but that probably varies by manufacturer.
73, matt W6NIA On Wed, 19 Feb 2014 13:29:22 -0500, you wrote: >I get this type of noise when my wife uses a laminator. >I also get a lot of sporadic noise in the morning around the time people get >up which I assume are hair driers and curling irons. >It really could be anything, but probably something one of your neighbors has. > >Good luck finding it, if it continues. >73- Tom - wa4ta > > >> From: phys...@mac.com >> Date: Wed, 19 Feb 2014 10:15:42 -0800 >> To: Elecraft@mailman.qth.net >> Subject: [Elecraft] Noise, RFI ? >> >> Using my K3 I was trying to pick up a ZL2 station (New Zealand) around 18.08 >> MHz this morning (about 9:50 AM PST) when this huge noise blanketed >> everything out. It was about 30/9 and absolutely solid across the spectrum >> shown on the P3. Using my KPA500, I switched to the 20 meter band -- same >> noise, same level, same broadband impact. >> >> I determined that the noise was from roughly 1400 KHz all the way up to >> 28.05 MHz. All about 30/9. About the time that I finished checking this >> full MF/HF spectrum of noise it switched off. >> >> Then, it switched on, and stayed on for about 5 seconds, then off again. I >> turned on my Icom R75. The next time the noise came on I checked it with >> the R75 and the same noise, same 30/9 level, same broad across the bands. >> >> Obviously man-made or under man control as it switched on and off and was on >> for various periods of time. This noise seems to be close, like generated >> in the neighborhood someplace. >> >> Anyone have ideas of the cause. You noise experts (Jim?) should have ideas. >> I was thinking maybe an arc welding machine but that is just a wild guess. >> It sure seems to be something that can be switched on and off. It is not >> periodic in that the on/off switching is at varying intervals. The longest >> on period is about one minute, the shortest on period about 2 seconds. And, >> it has been quiet for the last 10 minutes or so. >> >> Thanks for your help. >> >> 73, phil, K7PEH >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Elecraft@mailman.qth.net >> >> 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:Elecraft@mailman.qth.net > >This list hosted by: http://www.qsl.net >Please help support this email list: http://www.qsl.net/donate.html Matt Zilmer, W6NIA -- "Give me six hours to chop down a tree and I will spend the first four sharpening the axe." -A. Lincoln ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
