Yaesu FT-897 Noise Blanker
During the 2004 ARRL 10 meter contest I was plagued with severe power line noise. The noise originates from a utility pole in my neighbor's front yard and I promised myself I'd QSL the spark gap transmissions by the power company. Since the conditions were not very good, I had plenty of opportunity to make a recording to document the effectiveness of the noise blanker in the FT-897.
The first 3.5 seconds of the recording below will let you listen to the power line noise with the noise blanker turned off but with the DSP Noise Reduction turned on. Then I turned on the noise blanker and the power line noise virtually disappears. After another 3 seconds or so I switched the noise blanker off again.
The image above shows the signature of the sound sample and the pictures below are of the FT-897 display with the noise blanker turned off and on.
As you can see, the noise level was a solid S9 and virtually disappears when the noise blanker was switched on. Of course I was fortunate that the noise was pulsating in nature or else the effect would not have been so dramatic. It did however make the difference between being able to participate in the contest or raking leaves. :-)