¿ªÔÆÌåÓý

  1. BITX20
  2. Messages
Single Messages Topics Expanded Polls

Re: #sbitx mod #sBitx

 

Scott,

I think you're probably good to go at this point. Extra bypass filtering on the output never hurts. In the olden days of HAM radio, 60/50Hz hum was the big problem with power HV power supplies.

If your scope has Math functions you could use the FFT math function to look at the 200kHz signal and its harmonics. Otherwise, an AM radio would work to see if there are harmonics being generated around 600kHz- 700kHz and 1000kHz-1750kHz. Just tune across the AM band and see if you pick up something then turn the buck converter off to see if it's the source.

On Tue, Aug 16, 2022 at 5:54 PM Scott KE8KYP <scott_massey@...> wrote:
Hi Jerry,

Ok, I see.? That makes sense.? It looks like there is very little real energy in the above 200kHz range (if any).? The only other thing I have tried was a cap on the output.? The larger the output cap, +1000uF, the overall ripple reduces.? I probably need to build a filter for the output and make some tests.? Can't do anything else.? DigiKey is late.

I've only got an oscilloscope to work with and I've not installed the converter in the radio just yet.? I'm not exactly sure how to look for harmonics without an analyzer.? Can you suggest another way to look?
? ?
Thanks again, Scott



--

Jerry, AC9NM
ÊÖÖеÄÄñÔÚ¹àľ´ÔÖÐÖµÁ½¸ö
Join [email protected] to automatically receive all group messages.