Topband: Low band noise

[Carl Braun]

Bruce

I work with AC inverters for industrial motor control and their presence obsoleted one of my competitor's overhead crane radio control product practically overnight.  A simple hand held AM "transistor" radio was placed within 50' of one of these motor Variable Frequency Drive (VFD) controls and you could hear the varying frequencies being generated by the IGBT transistors.  The competitor remote controls were operating in the 200-400 KHz band.  Pray for dead calm winds at SR and SS.

Carl AG6X

-----Original Message-----
From: Topband [mailto:topband-bounces at contesting.com] On Behalf Of Bill Cromwell
Sent: Tuesday, February 11, 2014 1:39 PM
To: topband at contesting.com
Subject: Re: Topband: Low band noise

Hi Bruce,

I assume your noise is on top band (just a wild guess). I will lay on plans this weekend to drive a ways south with the R-599 on 160 meters AND an AM broadcast band receiver that allows some directive sniffing to see if the windmill farm down that way is um... 'polluting'. I haven't looked that far ahead on the weather forecasts. If it's icy or there is a blizzard this old goat ain't going there. In the process I suppose I'll find out if my car is 'clean'. I've been lucky so far.

73,

Bill  KU8H


On 02/11/2014 03:58 PM, Bruce 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
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