[RFI] Sinusoidal type noise on 6 meters

[Jim Brown]

On 11/20/2023 1:16 AM, Jim Brown wrote:
> 
> This is clearly power-handling electronics,

Some tutorial thoughts for those with less technical background, and who 
have not taken the time to study enough to have earned their license, 
which both requires and depends upon technical competence! We have the 
operating permissions we do BECAUSE we supposed to be are technically 
competent. I am one of many who studied the ARRL License Manual to pass 
our license exams (me at age 14), but the responsible ham goes back and 
works to actually LEARN that stuff. For many of us, it led to a career 
in some form of electronics or communications. I ended up in 
broadcasting and pro audio; others put us on the Moon and Mars. K4BAI 
and W6OAT, both of whom I worked fairly often as teenagers, became 
lawyers and a bankruptcy judge. At age 82, I'm still trying to learn new 
stuff, and all my life I've tried to share what I've learned.

Traditional power supplies rectify to produce half-sine DC, which must 
be filtered to produce DC. Because the power frequency is 60 Hz, that 
requires larger filter caps (translate to more expensive and large).

Switch-mode power supplies include the traditional power supply, but 
then use that DC to produce square waves in the range of 10 kHz; their 
period is FAR shorter, so the required filter caps are MUCH smaller, and 
cheaper. As one of the earliest measures to save energy, switch-mode 
power supplies were mandated by law a couple of decades ago, but 
Congress failed to fund the FCC to enforce their own Rules (Federal Law) 
that required that they not cause harmful interference. It is safe to 
assume that 99.9% of these products are noise generators.

73, Jim K9YC