[ARC5] SCR-274 calibration Xtals

[Richard Knoppow]

    I was thinking the same thing. By now the crystal is probably 
perfectly stable.

On 8/19/2016 12:37 PM, Bill Cromwell wrote:
> Maybe the crystal started out 70 years ago at 10 kc low <evil grin>.
>
> 73,
>
> Bill  KU8H
>
> On 08/19/2016 01:31 PM, Kenneth G. Gordon wrote:
>> On 18 Aug 2016 at 14:57, J Mcvey via ARC5 wrote:
>>
>>> Just for fun, I decided to see how the magic eye transmitter
>>> calibration system
>>> worked in practice. It actually worked pretty well, but the
>>> resonance  was at
>>> 3502 khz instead of 3500 khz ( marked on xtal) .
>> Gee!! That close? That is amazing for a crystal which is over 70 years
>> old...not to mention the other components in the circuit which could
>> effect the
>> resonance frequency,
>>
>>> Is this typical?
>> No. It is far too good. Typically, crystals drift upwards a certain
>> amount per
>> year. By now, it should have been a lot further off.
>>
>> As others have mentioned here, you can tweak it exactly on to frequency
>> with external components. Parallel capacitance will lower the frequency.
>>
>> Ken W7EKB
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>

-- 
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL