Using Keysight's Advanced Design System EDA, I created a basic model of the bandpass filter as it currently stands on the pull-out-structure:
This compares very closely to the measured values from the NanoVNA but is distinctly different from those from a simulation of ideal components:
I am currently considering two options:
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- Institute a high-pass filter instead of the bandpass filter and cut off harmonics after the PA with a phyisically bigger filter
- Utilize a band-stop filter to reduce the cutoff that the bandpass filter must have to eliminate the 105.6 MHz unwanted mixer product.
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