[RFI] RFI on 160 meters at WD8DSB from Hi-Fi Amp or its power supply 0.27 miles away.

[Jim Brown]

On 4/8/2022 5:51 PM, Don Kirk wrote:
> Turns out the RFI was from a Hi-Fi Digital Amplifier MN180BT or its
> power supply located 0.27 miles from my house.

The clue may be "Digital Power Amp," meaning not an analog output stage, 
but a digital one, known in that world as "Class D." In which case the 
output stage is not properly low-pass filtered differentially, and the 
antenna would include speaker wiring. If you can chase down a mfr, that 
might help.

Some fixes if it's differential -- replace speaker wiring with twisted 
pair. If they're audiophiles, use #12 twisted (homebrew by twisting with 
a drill motor with the other end in a bench vise). Twist it more than 
you need, let it sit at least overnight before releasing. It will 
untwist a bit, but that won't matter.

For common mode, of course, the usual turns of #31.

Let us know what you learn at what works.

73, Jim K9YC