[time-nuts] AN/URQ13 reference AT cut crystal?

[paul swed]

After a bit of research I am wondering if this odd unit was actually an
attempt at a AT cut crystal reference. The temperatures seem to line up.
Its certainly an alpha or less product.
It was stable at 43 F.
Was thinking about disconnecting the oven and bringing the leads out to
manually control the temp. With a quality external temp meter. Then see as
the temperature is adjusted, does it follow an AT cut curve.
As someone on the thread said "it maybe working as intended".
Regards
Paul
WB8TSL

On Tue, Feb 16, 2021 at 6:17 PM paul swed <paulswedb at gmail.com> wrote:

> Hello to the group still working and decoding the AN/URQ-13 reference
> oscillator. Bob had mentioned that the crystal should be at 85 C and thats
> right for a SC cut crystal. Would there be any reason that this oscillator
> is perhaps a AT cut crystal thats in the 30 C range. Just odd that the
> front meter reads in the normal temperature range and the real
> measurement is 40C. Makes no sense but they build AT cut crystals for some
> reason.
> Ehat about the smaller ovens like Piezo's. Pretty sure I can find many
> details on the Morion oscillators like the MV200.
>
> Other bits of details.
> There are 2 discreet regulators that simply produce most likely a low
> noise +/-8.5V. The Oven heaters seem to run on +15V and the divider analog
> circuits need 13V min to work. But not 15V. That seems to cause some
> distortion.
> The other circuit on the board attached to the oscillator is a buffer amp.
> It does have several meter resistors on it also.
>
> Regards
> Paul
>