I listen to AM sports talk radio in my job trailer at work and notice that whenever anyone uses an AC motor on site, (Circular saw, corded drills, theading machines) , anything with coils and brushes, I get horrible static through the radio. Is there a filter to eliminate this noise?
You might try a differrent kind of radio. Like one of those that are made by tool manufacturers for job sites. They have a lot of shielding around the tuning circuits to reduce the amount of EMI from power tools that gets picked up by the tuning circuits. You can't use a filter to reduce the noise. You need better RF shielding.
Am Radio Interference Filter
This Site Might Help You. RE: Is there a filter for noise through AM radio caused by EMI of AC motor? I listen to AM sports talk radio in my job trailer at work and notice that whenever anyone uses an AC motor on site, (Circular saw, corded drills, theading machines) , anything with coils and brushes, I get horrible static through the radio. Is there a filter to eliminate this noise?
There's not a lot you can do for this. If your radio is plugged into the A.C. outlet, you might get some improvement using an APC Power Line UPS, 350VA. They have some degree of filtering on the incoming AC line The interference is what's called RFI - Radio Frequency Interference. It is caused by the brushes against the commutator of those AC Motors. The motors generate square waves at a fairly high frequency (although not RF), but square wave have harmonic content that goes way high in frequency, into the AM Radio Band. It doesn't take many millivolts of RFI to interfere with your radio. Your only other solution would be to rotate the radio to see if you can get the radio's internal antenna parallel to the direction of the motor, to minimize reception of the RFI, while still being in a direction perpendicular to the radio station's transmitter. You may try tuning in a different AM station to see if you can get this parallelperpendicular path at an optimal point.
