[ARC5] SCR-274 calibration Xtals

[Richard Knoppow]

    This is 0.06% approximately, actually pretty close.  Most crystals 
can be pulled a little by adjusting the parallel capacitance. Have a 
look at the schematic to see if there is a capacitor across the crystal. 
  Might just be circuit capacitance. Adding capacitance will generally 
pull a crystal a little low so you might be able to put this one right 
on the nose.
    If this is an original WW-2 vintage crystal remember the technology 
of making crystals has changed enormously. I would still consider 2 Hz 
very close.

On 8/18/2016 4:28 PM, k1uhy at comcast.net wrote:
> I wouldnt bank on an almost 80 year old rock being forever accurate or
> even dead on from new. What was the original tolerance spec?
>
> ------------------------------------------------------------------------
> From: "J Mcvey via ARC5" <arc5 at mailman.qth.net>
> To: arc5 at mailman.qth.net
> Sent: Thursday, August 18, 2016 10:57:08 AM
> Subject: [ARC5] SCR-274 calibration Xtals
>
> 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) . Is this typical?
> BTW, does anyone have the 8000 khz xtal( I think that's what it's
> supposed to be) for the BC-459 to sell?
>
> JIm
>
>
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-- 
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL