Tony,
Good to see these results.
My SAW filters have exactly the same ripple and loss. It's a pity but my tinySA does not seem to bother much
Out of curiosity you could try to measure a single saw filter and see if (times 2) the results are the same. If not then the direct connection between the two filter is an issue and a series inductor (or even an LCL network) could be considered
As you seem to be able to mill away the copper rather accurate you may consider milling the rather simple footprint of the saw filters and solder them as they should be (not dead bug).
Or you can consider a copper foil at both sides of the SAW filter to create a massive ground plan
W.r.t the? measurement with the nanoVNA for the out of band rejection:
Can I suggest you calibrate the nanoVNA S21 with an amplifier (say 20dB) and an attenuator(say -20dB) between port 1 and port 2?.
When you measure the filter S21 you than remove the attenuator but keep the amplifier between the output of the SAW filter and port 2 and you have 20dB more dynamic range
This is possible because he SA612 mixers have their signal levels set for the fundamental but you measure a 10dB lower 3rd harmonic through a filter with 10dB loss (as you measure above 300MHz)?
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HBTE Files section:?
/g/HBTE/filesErik, PD0EK
