Matching Xtals for Filters

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From: Ed Tanton (n4xy@bellsouth.net)
Date: Wed May 28 1997 - 15:07:16 EDT


In a word Tim: no. It IS a thought: if you had "perfect pitch" AND a
receiver that was stable to several cycles short term-or rather for the
time necessary to compare enough crystals to find your matches... then
maybe. But I question whether a person can distinguish differences in the
tens of cycles (OK: Hertz.) Personally I don't think so. I THINK you would
want crystals as perfectly matched as possible... some of you crystal
filter gurus can answer that. But overall as to this idea as a method, I
don't think so. It NEVER hurts to ask Tim. How else are we going to learn.

At 01:58 PM 5/28/97 -0800, tim_hynde@idecc.com wrote:
>
>
> Gang:
>
> Don't laugh out loud but:
>
> When hand picking crystals for a filter network, can you do it by ear?
> That is to say, can you plug them into an oscillator circuit and
> listen on a receiver for the ones closest in tone? Or are you looking
> for much more precision?
>
> How close should they be to each other? What can I expect?
>
> What if I just use four from the same batch? If they are off a little
> how much will it affect the final result?
>
>
> Tim, ka8ddz
>
>
>
>
>
>
72/73
__________________________________________________________
Ed Tanton N4XY EMAIL: n4xy@bellsouth.net
189 Pioneer Trail
Marietta, GA 30068-3466 TEL: (770)579-3933 V/MBX/FAX
__________________________________________________________
QRP-ARCI #7663 G-QRP #6779 OK-QRP #172 QRP-L #758
AdvRC #140 NORCAL #1779 NCDXF SEDXC

Life Member: ARRL AMSAT INDEXA QCWA
__________________________________________________________

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