Yes, in many of the more recent Rb standards you're lucky if the crystal
is ovenized at all. But are you sure that they're after good ADEV? I
get the impression that the only thing they're interested in is low
drift for the unit (e.g. for holdover purposes) since they're intended
to be components in a system rather than lab standards. Anything else
is more luck than intent. The PRS10 seems to be an exception in that it
has an SC xtal. Other than the 5065A, are there any Rb standards that
use an SC xtal?
Ed
On 8/27/2013 6:24 PM, Bob Camp wrote:
Hi
The "OCXO" in most Rb's isn't all that great. They are after good ADEV, but
tempco and aging aren't terribly important.
Bob
On Aug 26, 2013, at 1:34 PM, Nathaniel Bezanson <[email protected]> wrote:
At room temperature, mine takes about 3-4 minutes heating until the lamp will
start. You'll see RbMon showing SD2 and AD4 at max values, then they'll settle
back into something sensible once it lights up. After that, you're watching the
DS signal values and hoping the (large, small) turns into (small, large).
Mine had a blown capacitor in the lamp circuit, thus it wouldn't ignite; SD2
and AD4 never budged. I opened it up to find a cracked tantalum cap:
http://imgur.com/bASgB After replacing the cap, I now get lamp ignition but it
doesn't achieve lock. (Photocell signal AD9 very low.) Once I swear I saw RbMon
claim it had locked, about 6 minutes after power-up, but a moment later it was
back to unlocked state and it's never repeated that feat. No idea what happened
there.
I'm wondering whether one can simply use it as a nice (albeit power-hungry)
OCXO. If given 1pps from GPS, will the quartz discipline itself even without
the Rb loop running?
-Nate B-
Stephen Tompsett (G8LYB) wrote:
Use the RbMon utility to monitor the unit's operation as it
starts up to
confirm that the lamp is started and the photocell is detecting a signal.
Not long ago there were a number of units available for sale on Ebay
that appeared to have a lamp problem.
On 23/08/2013 02:10, Paul wrote:
As I patiently wait for my PRS10 to lock I'm curious if there's a
limit beyond which I should assume the unit is faulty.
It does produce abount 10MHz (+- .2 Hz) and the oven current dropped
at what I assume is operating temperature.
--
Stephen Tompsett (G8LYB)
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