[R-390] Wanted: 14mHz Crystal

[Francesco Ledda]

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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