[Boatanchors] Testing a crystal

[Rob Atkinson]

Gary that's good to know and I guess someone could fire up a VFO
somewhere nearby and key it and use it to sweep across the xtal
frequency, or if not a ham band rock, then use a HP606 or some other
sig gen.

Rob
K5UJ

On Sun, Jul 8, 2018 at 12:23 PM, Gary Peterson <kzerocx at rap.midco.net> wrote:
> This reminds me of something I read in Hints & Kinks in a 1930s QST.
>
> The piece said that a crystal could be tested by placing its pins in series between a random length antenna and the antenna terminal of a receiver.  When the receiver is tuned to the resonant frequency of the crystal, there is an obvious change in the sound of the random noise coming out of the speaker.
>
> I mentioned this to a friend at coffee one evening.  He was skeptical.  We went to his QTH and he brought out a box full of crystals and some clip leads.  By golly, it worked.  The noise sounds just like what happens when you kick in a crystal filter in the IF of a receiver.  This seems to be a stress-free method of measuring the approximate frequency of a crystal.  Obviously, its exact frequency will depend on circuit parameters.
>
> Gary, K0CX