SolderSmoke Challenge – Bonus Episode – Using your oscilloscope to test your DCR
New homebrew radio builders often struggle with test and measurement. You can build a board perfectly but if you don’t have your tools setup correctly you won’t be able to tell if your board is working, or worse you’ll thing it is not working when it is working perfectly. In this bonus episode Dean, KK4DAS takes us through the basics of configuring and oscilloscope to test the boards, particularly the PTO oscillator, buffer, and the mixer.
We say this often, but if you really want to learn about oscilloscopes and test and measurement there is no better resource than our friend Alan, W2AEW’s YouTube Channel. Check it out!
Alan Wolke, W2AEW’s YouTube Channel:
https://youtube.com/@w2aew?si=
Join the discussion - SolderSmoke Discord Server:
Documentation on Hackaday:
https://hackaday.io/project/
SolderSmoke YouTube channel:
https://www.youtube.com/@
SolderSmoke blog DCR posts:
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Fine demo. I think that limiting 20 MHZ on a 100 MHZ oscilloscope is okay, but look at both
ReplyDeletefull bandwidth and limited bandwidth traces for high frequency. We can't ignore that the oscillator really has harmonics and harmonic # 2 is 14 MHZ harmonic #3 is at 21 MHZ. Apply the 5x rule if possible. This means you should select an oscilloscope with a bandwidth at least five times higher than the 7 MHZ frequency. So full 100 MHZ bandwidth is the best you can do to cover 7 MHZ and the harmonic frequencies. Full bandwidth gives a more true representation and may show instability and transients at higher frequencies. Also to avoid aliasing or amplitude inaccuracies as much as possible.Fine video
Thanks - yes - limiting the bandwidth can lead to misleading results - particulalry if you are looking for harmonics with the FFT. It helps to limit bandwidth and filter high frequency noise when measuring very small HF and audio signals as we often do. The tutorial was meant to show folks who have never used a scope basic settings so they can complete our Challenge project. We found a number of folks whod didn't understand even the basics.
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