[R-390] Wanted: 14mHz Crystal

[Larry Haney]

Hi all,  To get the best frequency stability out of your 390x read my
short doc: 'R-390A Ovens and Frequency Stability' on our website.  The
type of crystals do make a difference.  Here's a link:
R390A Ovens and Freq Stability.pdf.

Regards, Larry

On Sun, Jul 5, 2026 at 6:55 AM Francesco Ledda via R-390
<r-390 at mailman.qth.net> wrote:
>
> It probably doesn’t matter, as the turning point of the original R-390’s crystal is at the operating point of the ovens, and most owners keep the ovens turned off.
>
> Best, Francesco K5URG
>
>
> Sent from my iPad
>
> > On Jul 5, 2026, at 07:00, Bob kb8tq via R-390 <r-390 at mailman.qth.net> wrote:
> >
> > Hi
> >
> > A generic crystal from Digikey is not going to have the same temperature characteristic
> > as the original. The radio may drift a bit as a result.
> >
> > it also may not have the ability to tune to the correct frequency.
> >
> > For < $1, try it and see is not that bad an idea. Just be willing to check things out a bit
> > and possibly buy a couple candidates.
> >
> > Bob
> >
> >> On Jul 4, 2026, at 6:42 PM, Fred Moore via R-390 <r-390 at mailman.qth.net> wrote:
> >>
> >> Bill (and others needing crystals),
> >>
> >> 1.  I do have one from an R-390 (not A) oscillator unit.  Fair Radio was
> >> selling these for $20 near their end, plus shipping.  Payment by check.
> >>
> >> 2.  But other crystals will fail from time to time.  So I went on
> >> Digikey.com... They have a bunch of crystals, mostly SMD types.  These could
> >> be put inside the original holder.  Even MHz are pretty common there.  What
> >> about drive levels?  Is a tube osc too much drive for this little thing?
> >> There is a datasheet for it on this page.  So this approach might help others
> >> in the future.
> >>
> >> Here is one by CTS for $0.72:
> >> https://www.digikey.com/en/products/detail/cts-frequency-controls/406C35B14M00000/604558
> >>
> >> So this approach might help others in the future.
> >>
> >> -Fred
> >>
> >> ------ Original Message ------
> >> Received: Sat, 04 Jul 2026 05:22:44 PM GMT
> >> From: Bill Cotter via R-390 <r-390 at mailman.qth.net>
> >> To: r-390 at mailman.qth.net
> >> Subject: [R-390] Wanted:  14mHz Crystal
> >>
> >> Happy July 4th!
> >>
> >> Does anyone have a donor crystal bank with a 14mHz crystal they
> >> would be willing to part with? Please advise with price + shipping
> >> to my QTH (below).
> >>
> >> Thanks es 73 Bill N4LG
> >>
> >>
> >>
> >>
> >> ------------------------------------------------------------
> >> Bill Cotter, N4LG              E-mail: n4lg at qx.net
> >> 173 Carolyn Lane               Cell: (859) 552-7481
> >> Nicholasville, KY 40356-9340 https://www.qrz.com/db/n4lg
> >>
> >> ARCI #9878, QRPl #1646, QCWA #29393, FISTS #4535, NAQCC 7470
> >> ------------------------------------------------------------
> >>
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