Topband: Low band noise

[Herbert Schonbohm]

Bruce,  I can't answer your wind turbine noise question on TB but while 
we are on the subject and a bit off topic....in the 70's a 250KW wind 
turbine with metal blades was installed on the island of Culebra midway 
between Puerto Rico and St. Thomas.  As the blades were rotating they 
would shock modulate the TV signal reception of WAPA-TV and WKAQ on 
channels 2 and 4  causing what appeared to be hum bars rolling across 
the screen.  I ironically on a calm day the interference would 
disappear.  It was also determined that aircraft radar from the naval 
station Roosevelt Roads using the El Yunque Mtn installation and USN 
installation on Crown Mountain in St. often complained of refracted 
blips caused by the leading edge of the blades...at least that is what I 
was told by hams that worked their.  I think today and for that reason 
non metallic blades made from composite resins are required for the 
larger systems.


Herb Schoenbohm, KV4FZ




On 2/11/2014 4:58 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
> _________________
> Topband Reflector Archives - http://www.contesting.com/_topband