Well, Bruce, if they are using inverters forf the DC-AC conversion, I would expect I to be pretty nasty - some sort of "modified square wave" or "modified sine-wave" approximation. Like a HUGE switching power supply! And if it's tied to the grid or to transmission or distribution lines, it will be connected to large radiators that can radiate considerable harmonic energy over considerable distances. A cleaner way to do DC-AC inversion is with rotating machines (DC motors driving AC generators) but much more difficult to synchronize with the power grid. I doubt that those folks are paying a lot of attention to Power Quality!
Regards, Charlie, K4OTV -----Original Message----- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Bruce Sent: Tuesday, February 11, 2014 3:58 PM To: topband@contesting.com Subject: Topband: Low band noise Getting noise from my NW direction. Does not seem to be local. Started wondering what, at distance, could be causing it. At times it seems to have a rhythm like a motor. There are a lot of power generating wind mills showing up. Checking through Google, they generate DC and convert to 3 phase AC it with an inverter. The frequency and phase of the inverter is controlled with a sample from the power grid. Could their inverters have enough sine wave distortion to have harmonic energy? So my question is: Does anyone have first hand knowledge of interference on the low bands from power generator wind mills? Bruce-K1FZ www.qsl.net/k1fz/beveragenotes.html www.qsl.net/k1fz/pennantnotes.html _________________ Topband Reflector Archives - http://www.contesting.com/_topband _________________ Topband Reflector Archives - http://www.contesting.com/_topband