On Tue, 31 Aug 2010 17:02:16 -0700
John Miles jmi...@pop.net wrote:
Microwave test gear and plumbing is very significantly harder to get at 24
GHz than at 1.4 GHz.
At a guess I've seen easily 100 times more stuff available at 1.4 GHz.
That is so far down the list of 101 Things That
Hi
Indeed, there's not much you can do to figure out which of the two is
correct. This is well explained in the NTP doc's. My concern was that people
drop back to 1 or 2 servers from 6 or 8 and hop from one issue to another.
Bob
-Original Message-
From: time-nuts-boun...@febo.com
Hi
I have had great luck running the net4501 boards as NTP servers. As
previously discussed, they have some very real advantages over the 5501's in
this application. The onboard timing and PHK's code to use it really does
help.
Bob
-Original Message-
From: time-nuts-boun...@febo.com
Hi
Both seem to require a *lot* more work than a maser, not to mention a steady
flow of liquid nitrogen.
Bob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Heathkid
Sent: Tuesday, August 31, 2010 10:11 PM
To: Discussion of precise
Hi
Back up again on email. It's completely unclear who or what took things
down. It's also unclear what fixed it. All I can be sure of is I neither
broke it or fixed it. It came back up today at around 10.
I had an interesting conversation with an advanced tech support supervisor
at
Not unlike Cox. They generally provide great service, but when problems do crop
up (rare, but it has happened), the only thing that they guaranty is that you
will get their bill in the mail on time. Any more than that is just gravy...
Didier
Sent from my BlackBerry
Hi
My guess is that you put the adjuster entirely inside the vacuum enclosure.
Pump the gizmo down, stabilize it, measure where it's at. Do some math, pop
it open move the adjuster x.xx turns. Step and repeat. Possibly have a fine
and a coarse mechanical adjust screw.
It's a one time only sort
Hi
I suspect that it's not an unusual stance. If it is common, it would be
something to think long and hard about in a mission critical timing setup.
Bob
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Didier Juges
Sent: Wednesday,
Hi
My guess is that you put the adjuster entirely inside the vacuum
enclosure.
Pump the gizmo down, stabilize it, measure where it's at. Do some math,
pop
it open move the adjuster x.xx turns. Step and repeat. Possibly have a
fine
and a coarse mechanical adjust screw.
This kind of thing
So by those pictures you actually have it working?
Crazy question do you just drive down to your local air gas company and by
some hydrogen. How do you fill the red bottle?
Just down loaded the tech manual earlier printed out the ops manual.
Thanks
On Tue, Aug 31, 2010 at 10:35 PM, Tom Van Baak
Absolutely. I've found four to be best. That leaves you with three in the
event of a failure, but if you go to five or beyond often NTP will switch
from one time server to another which causes it to think the time has
radically changed, and the clock goes faster/slower/faster/slower for a bit.
On 09/01/2010 04:11 AM, Heathkid wrote:
How about a Laser-Cooled Mercury Ion Frequency Standard?
http://tf.nist.gov/general/pdf/1225.pdf
I have way too little liquid helium dewar flasks at all... but sure, it
would be fun. I would certainly see a bunch of challenges in mixing down
from about
On 08/31/2010 06:10 PM, Colby Gutierrez-Kraybill wrote:
Hello,
I'm on the hunt for relatively inexpensive GPS based NTP time servers.
Mainly, I'm looking for a survey of such items beyond the standard
Symmetricom, Meinberg and CNS product lines.
add
Spectracom
Oscilloquartz
to your list.
On 9/1/2010 12:18 PM, Bob Camp wrote:
Hi
My guess is that you put the adjuster entirely inside the vacuum enclosure.
Pump the gizmo down, stabilize it, measure where it's at. Do some math, pop
it open move the adjuster x.xx turns. Step and repeat. Possibly have a fine
and a coarse
In message 24c547b54ea34a69bacc4f823bb40...@pc52, Tom Van Baak writes:
I found the original copies of both EFOS manuals, along with
a few photos. See:
http://www.leapsecond.com/museum/efos/
Interesting.
Page 4/3 in the service manual states:
For the Hydrogen Maser, this
On 09/01/2010 09:39 PM, Poul-Henning Kamp wrote:
In message24c547b54ea34a69bacc4f823bb40...@pc52, Tom Van Baak writes:
I found the original copies of both EFOS manuals, along with
a few photos. See:
http://www.leapsecond.com/museum/efos/
Interesting.
Page 4/3 in the service manual
In message 4c7eb129.2090...@rubidium.dyndns.org, Magnus Danielson writes:
On 09/01/2010 09:39 PM, Poul-Henning Kamp wrote:
Yes, but what is the issues relating to sapphire loading? What's the
cost of the sapphire block and having it machined?
It is a saphire tube, a readily available, if not
Magnus Danielson wrote:
On 09/01/2010 09:39 PM, Poul-Henning Kamp wrote:
In message24c547b54ea34a69bacc4f823bb40...@pc52, Tom Van Baak
writes:
I found the original copies of both EFOS manuals, along with
a few photos. See:
http://www.leapsecond.com/museum/efos/
Interesting.
Page 4/3
In message 4c7eb534.2040...@xtra.co.nz, Bruce Griffiths writes:
The tempco of the dielectric constant of sapphire is quite large so the
cavity resonance tempco is somewhat larger than that of an unloaded
copper or aluminium cavity.
Yes, they write that cavity autotuning is a must.
I still
Given the quality of vacuum the manual seems to imply, I'm guessing this
wont cut it. I'll bet that even low impurity Teflon has a long bakeout
period.
Too bad they don't have some kind of getter to allow lower vacuum specs.
I expect they thought of that.
The thing does sound like a
An early analysis of a fused silica loaded cavity by Sigma Tau:
http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA497003Location=U2doc=GetTRDoc.pdf
http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA497003Location=U2doc=GetTRDoc.pdf
Although the dielectric constant tempco and thermal expansion tempco of
On 9/1/2010 3:30 PM, Chris Howard wrote:
Given the quality of vacuum the manual seems to imply, I'm guessing
this
wont cut it. I'll bet that even low impurity Teflon has a long
bakeout
period.
Too bad they don't have some kind of getter to allow lower vacuum
specs.
I expect they
Paul,
Yes it is operating.
With the exception of some down times to replace each of the ion pumps
when they failed (at separate times) it has been running nonstop for 3
years.
I also had to replace the disassociator oscillator with an
oscillator/amplifier of my own design.
Also replaced the
You can pickup oil diffusion pumps pretty inexpensively. They're not quite
ion pumps but they get you way down there and they're fast. With proper
traps you don't really have to worry about coating your experimental physics
package with oil. They're cheap to run and easy to maintain. Ion
An Ion pump is a kind of getter, on steroids.
-John
=
Given the quality of vacuum the manual seems to imply, I'm guessing
this
wont cut it. I'll bet that even low impurity Teflon has a long
bakeout
period.
Too bad they don't have some kind of getter to allow lower
Corby,
It might be easier to just make an adapter for Lecture Bottles for the H2
supply.
Also, the H2 probably does not have to be Research Grade. The inflow is
through a Palladium Valve which is a diffusion device ans only passes H2
at any significant rate.
Best,
-John
=
Paul,
Hi
You can get epoxies with very low outgassing numbers. Also you will be using
very little of it.
Bob
On Sep 1, 2010, at 3:28 PM, Oz-in-DFW li...@ozindfw.net wrote:
On 9/1/2010 12:18 PM, Bob Camp wrote:
Hi
My guess is that you put the adjuster entirely inside the vacuum enclosure.
Hi
My guess is that you either need a cryo pump or ion pumps and a very good seal.
Bob
On Sep 1, 2010, at 5:15 PM, Robert Darlington rdarling...@gmail.com wrote:
You can pickup oil diffusion pumps pretty inexpensively. They're not quite
ion pumps but they get you way down there and
Yup. If you do use oil, you need an LN2 trap.
-John
===
Hi
My guess is that you either need a cryo pump or ion pumps and a very good
seal.
Bob
On Sep 1, 2010, at 5:15 PM, Robert Darlington rdarling...@gmail.com
wrote:
You can pickup oil diffusion pumps pretty
And cryo means ultra high purity helium. I learned about that the hard
way. They don't like pumping gravel (solidified trace amounts of oxygen,
argon, etc.)
-Bob
On Wed, Sep 1, 2010 at 5:37 PM, J. Forster j...@quik.com wrote:
Yup. If you do use oil, you need an LN2 trap.
-John
Boards will be here Friday September 3.
Stanley
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Corby
Thanks. So it really uses very little hydrogen then. I was wondering about
the refill process.
Definitely like the red glow of the hydrogen.
I find the unique orange/purple hue of the RB interesting. Have seen it
while trying to get the last ounce of life out of old telco Rbs.
On Wed, Sep
Hi
My guess is that you're already stuck with ultra pure gas to get it working as
a maser.
Bob
On Sep 1, 2010, at 8:40 PM, Robert Darlington rdarling...@gmail.com wrote:
And cryo means ultra high purity helium. I learned about that the hard
way. They don't like pumping gravel
Reading the tech manual. The Hmaser only draws 100 watts. Thats far less
then I thought it did. I guess the shear size of the cavity makes it appear
like a power beast.
On Tue, Aug 31, 2010 at 5:29 PM, Corby Dawson cdel...@juno.com wrote:
The operation manual for the EFOS maser is on Tom Van
Apples and oranges.
What Robert presumably means is tha the working fluid (He) in the closed
cycle refrigerator used in a cryopump has to be extrremely pure to avoid
freezing up in the expansion engine at the cold side.
As I said before, the H2 probably does not have to be Research Grade,
On Wed, Sep 1, 2010 at 7:15 PM, Bob Camp li...@rtty.us wrote:
Hi
My guess is that you're already stuck with ultra pure gas to get it working
as a maser.
Bob
Ah, sorry. I meant in the pump, not the gas in the chamber. Solidifying
on the outside is fine. Inside tears them up.
-Bob
Is that anything like an Interocitor?
Bill Hawkins
-Original Message-
From: Corby Dawson
Sent: Wednesday, September 01, 2010 3:48 PM
- snip --
I also had to replace the disassociator oscillator with an
oscillator/amplifier of my own design.
More like the Plasma Balls the New Agers so love.
-John
Is that anything like an Interocitor?
Bill Hawkins
-Original Message-
From: Corby Dawson
Sent: Wednesday, September 01, 2010 3:48 PM
- snip --
I also had to replace the disassociator oscillator with
Hi Corby,
On the dissociator, do you have any indications that the helix on the bulb
is, in fact, a helical resonator for the dissociator frequency?
Also, when filling the H2 tank, you might want to put the receiver tank
into a bucket of water. It can really heat up during filling because of
Back when I worked with cryo-LNA's, we had helium for the cryo's and
nitrogen for the waveguide (to pressurize it). The cryo's were located
in a tropical environment and we had to add helium every day.
Then you get a new person, who comes back and ask if they were suppose
to use the pink
What was wrong with the original oscillator, out of curiosity? I'm
troubleshooting the lamp exciter in my 5065A right now, and the circuit is
the same basic series-tuned Colpitts design as the one on page 174 of the
maser's service manual.
The 5065A is showing occasional phase jumps on the order
They should never leak He. Were the lines between the compressor and the
head very long?
-John
===
Back when I worked with cryo-LNA's, we had helium for the cryo's and
nitrogen for the waveguide (to pressurize it). The cryo's were located
in a tropical environment and we had to
Thank you for making a homebrew H-maser look simple! :)
Magnus, That was sort of my point.
Can everyone do it? No. Can one (or more) of us do it... absolutely!
Especially if we work together on this. The amount of knowledge I've
already seen come out of this group *collectively* is
John,
I'd put money on one of the feedthrough caps (easily damaged upon installation)
in the Maser for such small jumps.
From memory, the 5065A uses SM components, but these could be guilty.
I've learned many abstract things I'd never otherwise come across in this
thread on home-built
Good point -- I should swap out the feedthrough as well. There is only one
in this case, for the power lead-in, but if it is growing internal whiskers
or otherwise failing I could see it causing this symptom...
-- john, KE5FX
-Original Message-
From: time-nuts-boun...@febo.com
Didier Juges wrote:
Not unlike Cox. They generally provide great service, but when problems do crop
up (rare, but it has happened), the only thing that they guaranty is that you
will get their bill in the mail on time. Any more than that is just gravy...
Didier
This is the fundamental
J. Forster wrote:
If you try to cut corners with high vacuun technology, you will be
disappointed. Even with all new parts and carefull assembly, you will
almost certainly have to He Leak Detect the system to get it tight. I've
done this stuff. It is doable but certainly not trivial. And you
paul swed wrote:
So by those pictures you actually have it working?
Crazy question do you just drive down to your local air gas company and by
some hydrogen. How do you fill the red bottle?
Just down loaded the tech manual earlier printed out the ops manual.
Thanks
Basically, yes.. you can
I noticed that after I hooked up my phone to the cable company my computer
connection became a lot more reliable. Both pass through the same modem.
In fact it has not been off since the hookup. I think they do try very hard
to keep the computer path on for those who also have the phone
The combination of high vacuum and milliKelvin temperatures is far, far
worse.
-John
J. Forster wrote:
If you try to cut corners with high vacuun technology, you will be
disappointed. Even with all new parts and carefull assembly, you will
almost certainly have to He Leak
If you decide to go the zinc/acid route (a very bad idea, IMO) you will
need a compressor. I'd not want anything to do with that! I like living.
A Lecture Bottle is the way to go.
-John
=
paul swed wrote:
So by those pictures you actually have it working?
Crazy question do
As that brings the mechanics inside the work envelope of main-stream
CNC machines with the required tolerances.
Yes, but what is the issues relating to sapphire loading? What's the
cost of the sapphire block and having it machined?
Sapphire is pretty inexpensive (relatively speaking)..
Poul-Henning Kamp wrote:
In message 4c7eb129.2090...@rubidium.dyndns.org, Magnus Danielson writes:
On 09/01/2010 09:39 PM, Poul-Henning Kamp wrote:
Yes, but what is the issues relating to sapphire loading? What's the
cost of the sapphire block and having it machined?
It is a saphire tube,
Bob Camp wrote:
Hi
My guess is that you either need a cryo pump or ion pumps and a very good seal.
Bob
You know.. a cryo/sorption pump might be the way to go. Easy to use
(just get some LN2) and they can pump down pretty fast. If you only need
one or two pumpdown cycles, that might be
jim...@earthlink.net said:
The gas diffusing out through the drilled bolt.. sure it's drilled, but the
conductance is so patheticaly low, you're literally waiting until the gas
molecules happen to randomly bounce their wey up the hole.
I've never worked with vacuum gear.
I assume drilled
J. Forster wrote:
If you decide to go the zinc/acid route (a very bad idea, IMO) you will
need a compressor. I'd not want anything to do with that! I like living.
A Lecture Bottle is the way to go.
Why would you compress it.. I imagine that you need micrograms of H2..
(it *is* almost a
Hal Murray wrote:
jim...@earthlink.net said:
The gas diffusing out through the drilled bolt.. sure it's drilled, but the
conductance is so patheticaly low, you're literally waiting until the gas
molecules happen to randomly bounce their wey up the hole.
I've never worked with vacuum gear.
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