[Lowfer] trimmer for pierce oscillator

[C. Turner]

Two words:

Series Inductor.

(More words)

A few microhenry variable choke in series with the crystal should be 
capable of moving the 1.7 MHz crystal down a few hundred Hz:  I find 
series inductors a bit more flexible in "rubbering" a crystal down in 
frequency than a parallel cap, as you can go only so far with a 
capacitor before the oscillator becomes too lazy.

Clint
KA7OEI/CT


Douglas D. Williams wrote:
> Years ago I built an LF converter from a design by Doug DeMaw and Jay
> Rusgrove that appeared in the June, 1977 issue of QST. It has proven to be
> an excellent design, outperforming two different commercial converters that
> I have tried out. 
>
> The local oscillator circuit in the converter is a simple Pierce oscillator
> designed around a 2N2222A transistor and a 1.7 MHz crystal. The crystal I
> have is 290 Hz high and I would like to add a trimmer capacitor to be able
> to adjust the frequency dead on so I don't have to do any mental gymnastics
> when trying to tune a certain frequency. 
>
> Here is a link to the schematic of the oscillator circuit:
>
> http://i81.photobucket.com/albums/j231/Goranothos/oscillator.jpg
>
>
> My question is where should I add the trimmer capacitor and what value
> should I use? 
>
> Thanks in advance for any help.
>
> -Doug KB4OER
>
>
>
> _______________________________________________
> >From the Lowfer mailing list
> Send messages to: Lowfer at mailman.qth.net
> To sub/unsub visit: http://mailman.qth.net/mailman/listinfo/lowfer
>
>
>