Hi All,
I have successfully used this method to retune 27MHz radio control crystals
to produce a couple of channel frequencies around 433.500 MHz (when
multiplied by 16).
I used a pencil rubbed gently on the surface of the crystal.
The crystal cans were of the "solder seal" type and all you had to do was
heat the case of the crystal with the tip of a soldering iron, and the lid
would come off. Unfortunately modern crystal cases are welded, and I have
not been able to get in without destrying the crystal element. (Anyone know
any tricks here ?)
I found it quite educational, because it make you realise that a crystal
frequency is determined by a mechanical resonance. Adding mass to the
surface lowers the resonance.
Nice to see it happen before your eyes.
73
Hugh M0WYE
On Sat, 19 Aug 2006 21:16:13 +0200 "Dick" <[email protected]> writes:
For those who didn't know, use following 'trick' to tune your own X-tal.
(found it in a magazine from the VERON)
Take an permant marker pen ("Edding, or similar) and put a little
stripe/line on the X-tal plate.
You will notice that the frequency goes down a bit.
|
