Topband: lift station noise

Lee K7TJR k7tjr at
Tue Apr 7 19:59:30 PDT 2009

Larry, for what its worth I have been through chasing noise from a pump 
as well. Many of the newer systems use what is called a VFD, variable 
frequency drive. Apparently there is some operating cost saving from 
reduced power usage. Unfortunately these things rectify and chop raw 
line voltages. The result is a lot of RF going back out the power lines. It 
may be interesting to note that most manufacturers of such devices also 
sell filtering devices to go with them. Unfortunately the manufacturer tells 
no one that they may in fact be illegal to operate under some 
circumstances so no one buys their filters. My local water company was 
very helpful when informed of their noise emanations I was hearing over 
a mile away on 160 meters. They installed the factory recommended filter 
and most of the frying noise went away. You can still hear it when driving 
by but not a mile away any more. I was successful by contacting the 
owner of the pump. Hopefully that will work for you. 
Lee  K7TJR  OR 

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