[time-nuts] Question for any HP105 owners

[Tom Van Baak]

Hi Mark,

What reference oscillator and measurement system did you use?
Is that with or without a sqrt(2) removed? Is your HP105 the older
style with the 00105 brick oscillator or a newer one?

The modern HP105 is essentially a well engineered wrapper around
a 10811 oscillator so the performance you see will be that of the
10811. Your 3e-12 measurement beats the spec for a 10811 (1e-11
at tau 100 s) by a wide margin.

It is possible that the 10811 used in HP105 met some higher spec
or were hand selected. I don't know. Perhaps someone from HP
(Rick?) could clarify this for us. We do know there are a number
of different grades of 10811.

One lesson you learn if you test many 10811 is that they can vary
by quite a lot (an order of magnitude or more), even those with the
same part number in the same instrument model.

For example, see the tau 100 second point of a dozen 10811's:
http://leapsecond.com/pages/z3801a-osc/z3801a-13-adev-m.gif
Notice they all are under the 1e-11 at 100s spec, but some are
much better than others. It's the luck of the draw. And one reason
why some of us troll eBay for old or cheap 10811 hoping to find
one that's better than the previous best.

/tvb

----- Original Message ----- 
From: "Mark Spencer" <mspencer12345 at yahoo.ca>
To: <time-nuts at febo.com>
Sent: Saturday, August 27, 2011 4:53 PM
Subject: [time-nuts] Question for any HP105 owners


> Just curious what a typical ADEV figure is for the HP105 ?  Mine seems to be approx 3X10-12 at 100 seconds.  Just 
> curious what results any other HP105 owners have seen in practice.
>
> Thanks in advance
> Mark VE7AFZ