[time-nuts] Ovenaire OCXOs

[Joseph Gray]

After running overnight, the current draw has stabileized at 160 mA. I
tweaked the trim pot to set the frequency to 10,000,000.00 Hz, which
is the resolution of my counter. The counter is synced to the Z3801A.
The Ovenaire is exposed to ambient air, so I expect things to change
as the day warms up.

Using an IR thermometer, the OCXO metal can temperature varies a bit,
but has a hot spot at 37.6 C. I'll have to dig out a contact
temperature probe for more accurate readings.

Later on, I'll put this thing in an enclosure, which should minimize
temperature effects. Then I can see where the temperature stabilizes
from the oven heat. The T.I. comparison will have to wait a few days,
as I need my laptop for something else tomorrow night.

Joe Gray
W5JG

On Tue, Apr 12, 2011 at 7:27 AM, John Green <wpxs472 at gmail.com> wrote:
> Interesting. I have several Ovenaire OCXOs of differing models. I used to
> think they were pretty stable until I compared them to my Z3801. Compared to
> a '3801, they stink. But then, a rubidium stinks compared to a 3801. Most
> have a voltage input for frequency adjustment but one has a trimmer cap for
> coarse and a pot for fine. Over a period of several days, I would think it
> had settled down only to come back and find it had suddenly shifted. As they
> say, stable is a relative term. About all I can say after testing maybe a
> half dozen from different manufacturers it that the specifications should be
> taken with a liberal dose of salt. I have seen TCXOs do better than a lot of
> OCXOs over the limited temperature range of my lab. I have a chamber and
> keep saying I am going to do some temperature testing but work is always
> getting in the way.
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