20 meter noise? - RFI Forum at eHam.net

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eHam.net Forum : RFI : 20 meter noise?

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20 meter noise?	Reply
by WALTERB on July 5, 2008	Mail this to a friend!
I'm pretty new to the hobby, and for some reason I get a lot of random interference on the 20 meter band. It should like someone with an electric pair of shears killing a cat. It comes and goes but no pattern. Any suggestions? thanks

RE: 20 meter noise?	Reply
by N3OX on July 5, 2008	Mail this to a friend!
Does it sound like this? http://www.n3ox.net/files/switcherQRM.mp3 That's from a switching power supply; some very high harmonic of the switching frequency, I think (so a tiny drift in the switching frequency causes a big drift in the harmonic). That was recorded on 17m in USB mode. Dan

RE: 20 meter noise?	Reply
by WALTERB on July 5, 2008	Mail this to a friend!
sounds similar as far as the randomness, but the pitch of yours sounds like wind blowing. mine sounds like more like a barber's clippers underwater. I guess I'll have to kill everything in the house and slowly turn things on until the noise re-appears. I'll have to wait until the wife and kid is gone, because they don't like it when I make them go "amish".. :-)

RE: 20 meter noise?	Reply
by N3VMC on July 6, 2008	Mail this to a friend!
Hey walt! Im having the same issue here so you guys must of read my mind! I turned everything off in my house and cut the main breaker. I powered up my ICOM Pro-III with the 12V supply I use for camping...and the noise was still there. Funny though it wasnt there a few days ago....and yesterday 12 meters was bad. Im using an older Cushcraft R5. I took my AM radio around while the power was off to sweep the house for any interference....and sure enough I found a nice blob of EMR in my living room along the party wall with my neighbor. It is a constant hum....sounds like an AC motor....right beind my entertainment center. I didnt find any other noise in the house. Vince N3VMC

RE: 20 meter noise?	Reply
by WD2AHP on August 16, 2008	Mail this to a friend!
If it's random it's probably local. There are so many devices that can cause RFI. Perhaps your neighbor has a plasma tv for instance. wireless networking systems, etc. It's very frustrating indeed :( http://www.westfloridacomponents.com

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