I had reason last night to use the Nano VNA for something and while i was at it, i grabbed down an Xtal filter i had built ages ago and put it on for measuring. If i recall right, and I would have to go and look in old blog posts, when I measured this using the Bode Plotter in the Red Pitaya it looked alot like Bart Simpson and had 5db of ripple in the pass band and very lossy. Well, better tool, better measurements and this does not look all that bad to me. The ripple is acceptable and actual loss in the filter is around 3db which is more than fine. Its not quite narrow enough for a CW filter, but its good enough to get started with.