Crystal characterization and filter design

This page is a place to put my notes and a few documents from a presentation I gave at the OzarkCon QRP convention in Joplin, Missouri in 2008.  My slide show was really too big (over 4 MB) in native PowerPoint, but I converted it into a PDF and made it much smaller.  Same for a Word document that covered the same stuff in greater detail.

It feels incomplete, but you should have seen me trying to cover all this ground in 50 minutes.  I think the crystal measurements topic is covered pretty well, but the filter design part is mainly a discussion and overview of available software design tools.

The following links are to my presentation's slide show and an accompanying text document.

Slide show PDF

Document PDF

I was lucky to find (or be found by) Darell Brehm, WA3OPY of International Crystals (ICM), who introduced me to Bill Carver W7AAZ, noted ham technical guru and author of a number of articles.  Darell took four crystals I had measured with my homebrewed circuits and did his own measurements with ICM's professional equipment, then sent them to Bill who did them on his vector analyzer.  So I had two good "controls" for my crystals and I compare the results with my own measurements in the slide show.

The links below are to a couple of documents Mr. Carver was kind enough to provide me.  First are his notes from a crystal filter presentation he did, I think at Dayton.  Next is a sketched out circuit he recommended to me for crystal measurements using the Hycas amplifier I mentioned having built  Note that his fixture puts the crystal in a one ohm (!) environment, necessitating a lot of gain -- use for the Hycas.

Carver lecture notes PDF

Carver crystal test circuit and notes PDF

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