Overview video looking at the design of a superhet CW crystal filter. The idea was to use a cheap NanoVNA from AliExpress and the 'Crystal Ladder Filters for All' paper from Jack Hardcastle G3JIR
Apologies that it is just an overview, but a detailed video would have taken well over a hour or so.
It was based on the following source/reference material:
Crystal Ladder Filters for All
https://www.arrl.org/files/file/QEX_Next_Issue/Nov-Dec_2009/QEX_Nov-Dec_09_Feature.pdf
Test Jig
http://qrp-popcorn.blogspot.com/2015/01/crystal-parameters-experiments-with.html
NanoVNA Control software by Rune Broberg
https://mihtjel.github.io/nanovna-saver/
Crystal Ladder Filter Program by Horst Steder DJ6EV
http://www.arrl.org/qexfiles