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AC line interference

I seem to have AC line noise imposed on my tranceiver's output signal and need a solution. My transceiver is a Yaesu FT-840 brand.

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I experienced very similar or the same problem with FT-840. When power is inceased over about 50 W, an AM on RF signal arises. Even when TCVR is supplied from accu and connected to dummy load. Period of interferencing signal is about 7.5 ms (130 Hz), so it cannot be hum from mains. I have not opened the PA block yet but i guess, it could be caused by damaged capacitor(s). Jiri

Posted on Dec 07, 2011


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