Hi
You do work pretty hard to turn the metal can into a getter. The other issue is
that
the adsorption and desorption rates are quite different. Once you get the
“stuff”
into a layer state, it takes a long time to get it back out. Much better to not
have it
there in the first place.
If the
It is possible that the ageing of a crystal is associated with the
redistribution of the surface water
monolayer, under the influence of the minute temperature gradient of an
oscillating crystal.
Some energy is dissipated in the quartz, so some gradient may exist.
When a crystal is resting, the w
Hi
Well one thing that happens is that the glue that holds the blank in the holder
turns to ash ….
Bob
> On Jun 9, 2017, at 8:31 PM, Hal Murray wrote:
>
>
>> You can’t quite process a crystal at 300C, but you can get close.
>
> What happens if you get it too hot or too long? What's the lim
alpha quartz to beta quartz phase transition at 573C amongst other factors.
Bruce
>
> On 10 June 2017 at 12:31 Hal Murray wrote:
>
> > >
> > You can’t quite process a crystal at 300C, but you can get close.
> >
> > >
> What happens if you get it too hot or too
> You canât quite process a crystal at 300C, but you can get close.
What happens if you get it too hot or too long? What's the limiting factor?
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Hi
You can’t quite process a crystal at 300C, but you can get close.
Bob
> On Jun 9, 2017, at 7:38 PM, Neville Michie wrote:
>
> My memory of high vacuum work is that you need to pump for 4 hours
> at 300C to remove the water monolayer from glass.
> On top of the that water monolayer is anoth
My memory of high vacuum work is that you need to pump for 4 hours
at 300C to remove the water monolayer from glass.
On top of the that water monolayer is another water monolayer that comes off
more easily,
and on top of that another………..
cheers,
Neville Michie
> On 9 Jun 2017, at 10:57 AM, Ri
Poul-Henning wrote:
Next down the line is hydrogen, which comes with a shitload of issues.
No argument there. But other methods all have their own shitloads -- it
just depends on which shitload the designers dislike the least.
you will find little love for hydrogen cooling [today]
In 199
In message <593a4677.5080...@yandex.com>, Charles Steinmetz writes:
>The insides of mains alternators are almost entirely metal -- tons and
>tons of copper tubing, and the casings and rotor shaft are steel. And
>the alternators must operate at a relative humidity of absolute zero.
Th
Hi
Cold traps and vac-ion pumps were very common on precision crystal seal setups
50 years ago.
They have gotten better since then….
Bob
> On Jun 9, 2017, at 9:13 AM, jimlux wrote:
>
> On 6/8/17 1:19 PM, Bob kb8tq wrote:
>> Hi
>>
>> If you look at the thermal conductivity vs very low pressu
Hi
My guess is that crystals are more sensitive to moisture than the alternators….
The level of “clean”
you need in a precision crystal enclosure is way beyond what is required in a
number of other areas.
One layer of water molecules is way to much in a modern crystal. can and do
use crystals
On 6/8/17 1:19 PM, Bob kb8tq wrote:
Hi
If you look at the thermal conductivity vs very low pressures, the conductivity
comes up pretty quickly from a hard vacuum. There is essentially no impact
on Q.
basically, when the mean free path gets to be shorter than the distance
to the wall, the the
ctive remover of heat :-))
> Alan
> G3NYK
>
> - Original Message - From: "Bob kb8tq"
> To: "Discussion of precise time and frequency measurement" <
> time-nuts@febo.com>
> Sent: Thursday, June 08, 2017 9:19 PM
> Subject: Re: [time-nuts] backfil
Wouldn't the low density of helium reduce some mechanical friction?
I realize the motions are small but they are motions.
The "Cousteau effect"? :)
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Bob wrote:
In this case hydrogen + oxygen (like from oxidized metal) goes to H20. You very
much do
not want water running around inside your crystal holder… Helium is inert.
The insides of mains alternators are almost entirely metal -- tons and
tons of copper tubing, and the casings and roto
Bob wrote:
You really want to use Helium. Hydrogen is a bit reactive.
I don't think it's a problem. The alternators on mains powerplants are
filled with Hydrogen under fair pressure, and the internal materials and
conditions are not that different from a crystal oscillator inside an
oven.
On 6/8/2017 5:08 PM, Bob kb8tq wrote:
Hi
In this case hydrogen + oxygen (like from oxidized metal) goes to H20. You very
much do
not want water running around inside your crystal holder… Helium is inert.
Bob
Exactly right Bob. The 10811 guys used to go nuts
about keeping water out of the
Hi
In this case hydrogen + oxygen (like from oxidized metal) goes to H20. You very
much do
not want water running around inside your crystal holder… Helium is inert.
Bob
> On Jun 8, 2017, at 7:18 PM, Charles Steinmetz wrote:
>
> Bob wrote:
>
>> You really want to use Helium. Hydrogen is a
Bob is exactly right. Read up on "mean free path" physics.
Just a little air will take care of conduction.
Full atmospheric pressure would drop the Q something like
a factor of 2.
In any event, conduction through the crystal mounts is
plenty adequate for the tiny thermal mass of the crystal
itse
; - Original Message - From: "Bob kb8tq"
> To: "Discussion of precise time and frequency measurement"
>
> Sent: Thursday, June 08, 2017 9:19 PM
> Subject: Re: [time-nuts] backfill (was: Poor man's oven)
>
>
>> Hi
>>
>> If you loo
9:19 PM
Subject: Re: [time-nuts] backfill (was: Poor man's oven)
Hi
If you look at the thermal conductivity vs very low pressures, the
conductivity
comes up pretty quickly from a hard vacuum. There is essentially no impact
on Q.
Bob
On Jun 8, 2017, at 4:03 PM, Attila Kinali wrote:
On
Hi
If you look at the thermal conductivity vs very low pressures, the conductivity
comes up pretty quickly from a hard vacuum. There is essentially no impact
on Q.
Bob
> On Jun 8, 2017, at 4:03 PM, Attila Kinali wrote:
>
> On Thu, 8 Jun 2017 06:55:07 -0400
> Bob kb8tq wrote:
>
>> The simpl
On Thu, 8 Jun 2017 06:55:07 -0400
Bob kb8tq wrote:
> The simple answer is that the backfill is done because it does matter in a
> lot of
> cases.
This raises the question, why there is backfill (just for thermal conductivity?)
and how much it affects the Q of the crystal.
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