Dino's FB W1FB Crystal Tester

A couple of weeks ago I noted that the complexity of DeMaw's circuit caused many of us to wimp out on this test gear project.  I joked that those who had built the device might be able to set up small businesses to do the testing for the rest of us.  Perhaps our friend Dino can cut a deal with G7WKE to divide up the world market for crystal testing: Dino could have the Western Hemisphere while Rob covers Europe and points East.  

Bill -

Enjoyed seeing someone else who has built Doug’s crystal tester on the blog.  Here’s mine, built this back in early 2007.  Anyone who wants to duplicate the tester can find the article in the January 1990 issue of QST or the updated article in the W1FB Design Notebook (page 192).  Note that the QST article has a missing component value and a missing component (both corrected in the Design Notebook):

(1) R24 is missing its value - it’s marked in the Notebook as 56 ohms.

(2) There should be a 220 ohm resistor connected between the output pin of U2 the LM317T regulator and the top of R1 the voltage adjust pot that is connected between U2’s adjust pin and ground [corrected in the March 1990 QST Feedback column].

I built a FT-243 adapter to let me work with larger crystals.

73 - Dino KL0S