I ran across this tip in an old radio magazine & thought it was well worth passing on.
A Ham had problems with noise on his receiver.
Nothing worked. He shut off all the circuits in his home one by one, even talked to his neighbors and was given permission to shut off their power to see if it was being generated in their home. (Geez- whsh folks were so cooperative nowdays).
He even talked to the power company troubleshooter, and he suggested the following:
Take a portable radio tuned to the freq the noise was on and go around to every power pole.
Whack the pole with a sledge hammer and see if it increased or decreased the noise.
About a block away he hit a pole and the noise changed drastically. He then called the power company, and they came out and located & replaced a defective insulator.
Problem solved with the use of a big hammer.
I had a similar problem here, with mass noise coming in from the power line. I contacted the local power company and the line tech called me back. When he found out I was a Ham, and not some nut case, he paid careful attention to what I told him & what I had tried.
I had whacked on poles all down my street and the entire area, with no change. I definately determined the noise was coming in on the power line.
About 2 weeks later the noise was gone. Another week went by and the tech called me. He asked if the noise was gone and I said "Yes Thank You". HE said they found a bad ground in the distribution system on a pole about 1/2 mile away, clear across the freeway. Problem solved, noisey reception gone, and another happy customer made.