Topband: Low band noise

[W2PM]

I just sent this to the fellow in Waco.   I'd recommend getting the PC ap called Zelscope which is a software based scope. It was ten bucks a few year ago. (there are also several free iphone aps which do this too - audio spectrum analyzers)  Hook receiver to sound Card and you can see the waveform, determine base frequency. You can then snapshot the screen and show the waveform which will have certain group of peaks.  Arrl would characterize as "3 peak, 4 peak, 5 peak" but you would also see if there are multiple sources of the noise or a single one. 

If this is a single source a MFJ1025 nuller will work nicely to eliminate it with the proper sense antenna and some twidling of the controls to null out the crud.

After years of working with ARRL and the power co here we identified 4 sources of gap noise and they they fixed all but one (because an idiot neighbor blocked access to the right of way and they haven't  got around to dealing with them yet since the problem isn't affecting safety or other power transmission issues.).  

But now with the sole source of crud I can null it out all the time on most bands including 160 but as you tune across the band you have to re null since the line changes the  crud noise phase along its length.  There are some frequencies where nulling can't be had (altho by reorienting the sense Antenna or setting up a second one it can. I have three sense antennas out there for this purpose. 

Sent from my iPad

On Feb 11, 2014, at 15:58, "Bruce" <k1fz at myfairpoint.net> wrote:

> 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