Time to Push the "reset button"
I hope we can all agree what one is not going to find an axes that makes
the
Frequency modulation that is caused by tapping on the Oscillator, or the
table or the airplane, or the boat, to go away, for whatever reasons.
Sorry, what I've been falsely referring to as the zero-G axes is actually
the "Zero Tilt" angle axes.
I have not had problems with My G changing short term, (BUT it would be
interesting to see if I can detect the moon overhead).
What I do have is some problems with the Osc tilt angle changing due to
its
position changing a little.
It is the Zero-tilt angle axes that works over a very small change of a
few
degrees at most.
On the other hand, the Zero tilt axes is in fact the Max G sensitivity
axes.
If you want the Min G sensitivity axes, so that there is no change when
turning the Osc over, That is 90 deg from the zero tilt axes, which is
also
how you make the Osc into its best Tilt angle meter.
What happens at any G value that is between +1 and -1, or is greater than
+1
or -1, I have not tested for, so I'm not qualified to speculate.
I am only stating that there is an axes where the Oscillator frequency is
exactly the same when you turn it exactly over.
AND this is NOT the axes you want to have, If it is going to be tilted
even
a sub sub fraction of a deg.
Now can we get back to making the 10811 Osc better?
ws
**********************
*************************
From: "Bob Camp" <[email protected]>
Hi
If your zero g axis only works over a 1/100 G range, you are looking at
something other than acceleration. If you have found an axis with a zero,
it
should be a just as much a null at 1 mG as at 1 G as at 10 G's. It's also
possible that your "zero" is actually a minimum below your test
resolution
and higher G's bring it up to the point you can measure it. There's no
guarantee of a zero being there.
Hitting the oscillator makes it vibrate in all three axis, that's not
going
to be suppressed regardless of which way you have it mounted.
Bob
*********************
On Mar 28, 2010, at 12:42 AM, WarrenS wrote:
Humm,
Have to admit, I did not consider that as a possibility before.
Maybe when I tap on it, its not microphonics after all that cause the
freq
to modulate, but the vibration of the inside stuff that is warming it
up.
For every action there is a reaction and for every nut there is a
wing-it-nut.
ws
*****************
Hi
If that's the result you are getting, you are measuring something other
than G sensitivity. Temperature effects possibly.
Bob
****************
On Mar 27, 2010, at 11:02 PM, WarrenS wrote:
Just a friendly comment about the Zero G turn over point and Vibration
Like Zero temp turn over, Special orientation of the OSC ONLY works
good
over a VERY SMALL range, (maybe a 1/100 of G change)
It would not help vibration and has no effect on microphonics which are
likely a bigger problem anyway.
Try taping you Osc, It's freq will go crazy if monitoring it at high
resolutions and bandwidths
ws
************************
Hi
The concrete basement floor is your friend.
Stay as far away from the blower on the furnace as you can. If you have
a
drop forge in the basement avoid it as well :)....
You will indeed have a seismograph, but not a very useful one. There's
not a lot of G's at seismic frequencies unless you live in an active
earthquake region. The fundamentals of G's and displacement vs
frequency
are in your favor in that respect.
Bob
On Mar 27, 2010, at 12:42 PM, Stanley Reynolds wrote:
Is the source of the vibration important ? I'm thinking that any
vibration that is not on the same axis as gravity. Walking across the
lab vs a fan that is out of balance close by. Would a suspended mass
mounting help with vibration isolation and damping with rubber pads
and
springs or would that just make a seismograph ?
Stanley
----- Original Message ----
From: Peter Vince <pvince at theiet.org>
To: Discussion of precise time and frequency measurement <time-nuts at
febo.com>
Sent: Sat, March 27, 2010 10:51:07 AM
Subject: Re: [time-nuts] Making a HP 10811 better
Warren,
If you turn over an oscillator, is the frequency change
completely reversible (to your "under 1e-12 resolution") when it is
restored? Thinking aloud, if an hour-glass is turned over twice, the
final level will be the same, but the grains will be mixed. A quartz
crystal, however, is solid, so hopefully nothing actually moves.
Presumably the zero-G axis is with the axis of oscillation at 90
degrees to gravity?
Peter (the "other" one :-)
Another thing I use it for is to test high resolution Freq meters.
Using a calibrated wedge that I can then slide under one edge of the
zero-G
Osc box, I can
make small, variable, repeatable, freq changes of under 1e-12
resolution,
something pretty hard to do otherwise.
If I want to make BIG changes like 1e-10, I can rotate the box on any
of its
sides and still use the wedge,
and for a quick check of new equipment, I just turn the box over
which
then
gives a couple of parts in 1e-9 freq change.
It makes a weird but simple and indispensable variable freq source
that
is
useful for many things, such as checking the LOOP TC of a TBolt.
_______________________________________________
time-nuts mailing list -- [email protected]
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
_______________________________________________
time-nuts mailing list -- [email protected]
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
