To get started building quartz crystal filters, it is recommended to buy a larger amount of crystals. Selecting then a few with almost similiar properties
dramatically simplifies the mathematics. For this task, we use the
Crystal Checker, which was developped only for exactly this task. Together with
a (high resolution) frequency counter, the quartz crystals may then be grouped, according to frequency.
Hint #1 : As IF filters are usually at "low" frequencies, we suggest you use fundamental quartz crystals only.
This covers the range to approx. 30 MHz.
Hint #2 : Do not touch the quartz crystals too long, as frequency will change by some Hertz.
Having done so, you may proceed to
find the "inner values" aka Replacement Circuit
The Downloads below refer to the
Crystal Checker.