PA tx and rx values - Githubissues

kamocat / uSDX

An effecient and lightweight HF radio

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PA tx and rx values #2

Open kamocat opened 4 years ago

kamocat commented 4 years ago

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 commented 4 years ago

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 commented 4 years ago

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.