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PA tx and rx values #2

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kamocat opened this issue Jun 27, 2020 · 2 comments
Open

PA tx and rx values #2

kamocat opened this issue Jun 27, 2020 · 2 comments
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help wanted Extra attention is needed

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kamocat commented Jun 27, 2020

We need a set of values for the low-pass filter on the power amplifier board, as well as the band-pass filter for the receiver.
A separate of values for each ham band is needed.
@kamocat kamocat added the help wanted Extra attention is needed label Jun 27, 2020
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kamocat commented Jun 27, 2020

I set up a simulation project in KiCad for testing filter values. I'm not sure about the drain capacitance of the BS170 or what effect the Miller capacitance will have, so it will probably need some tweaking.

@kamocat kamocat mentioned this issue Jul 2, 2020
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kamocat commented Jul 18, 2020 •
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Cees (PE1DDA) mentioned this nice little calculator:
htts://rf-tools.com/lc-filter/
It looks like a 7th order elliptic would completely eliminate our first harmonic, but a 5th order would fit well to our current design.

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