I periodically check that.
On Nov 12, 2016 5:43 PM, "Adrian Godwin" wrote:
> What if your shop reference were drifting up ?
>
>
> On Sat, Nov 12, 2016 at 11:25 PM, Joseph Gray wrote:
>
> > TCXO, not OCXO, but related. Sorry, but I have no graphs.
> >
> > I work for a municipal radio shop. We se
Hi
Exact info on mass transfer is a bit complicated. A 5 MHz 5th overtone is
a bit thicker and more massive than a 100 MHz 5th. Both are thicker (and
more massive) than a 100 MHz fundamental. On top of that the blank is not
equally sensitive to mass at all points on it’s surface. Finally, gold
Hi
It depends both on the DDS “firmware” and the DAC linearity. You can play games
to
come up with the firmware side of it. The normal approach is to design the part
so the
DAC dominates. More or less, "more firmware bits” is cheaper than improving
the DAC.
Bob
> On Nov 12, 2016, at 8:13
Those are wonderful plots :)
I vaguely recall that a 1ppm frequency shift is approximately equivalent to
the mass transfer of one molecular layer of a crystal. So at some point
your counting atoms if there was no noise, thermal disturbance, mechanical
disturbance...
On Sat, Nov 12, 2016 at 5:00 P
Attila wrote:
Yes, depending on the data you show, it is not clear
whether one should do a linear or a logarithmic fit.
When the purpose is correcting a GPSDO local oscillator during holdover,
it depends on how long one expects to trust the corrected frequency.
Practical realities make it po
kb...@n1k.org said:
> Yes, the FE-405 uses a DDS and a cleanup. Inside the cleanup loop the DDS
> spurs come straight through. Since the FE-405 compensates for all sorts of
> things, the DDS moves around a lot. Even a one bit change on a DDS will move
> spurs around. With an ever changing DDS, y
What if your shop reference were drifting up ?
On Sat, Nov 12, 2016 at 11:25 PM, Joseph Gray wrote:
> TCXO, not OCXO, but related. Sorry, but I have no graphs.
>
> I work for a municipal radio shop. We service radios that span 20
> years (through acquisitions, it was GE, Ericsson, Com-Net, M/A-
The EFOS2 has a small (approx. 4" X 10") aluminium compressed gas bottle.
I fill it to about 450PSI and it lasts about 3 years.
Most modern Masers use Hydride supplies like the Hydrostik I'm working to
install.
They can last up to 10 years.
This all predicated that you have no leaks!
Cheers,
Corby
Hi
In *general* the crystal in an OCXO should drift positive. The reason often
mentioned is fairly simple:
You can only get the blank + base plate + calibration just so clean. You can go
crazy getting the enclosure clean. The result is a long term mass transfer from
the blank (it’s “dirty”, lo
Helium
On 11/12/2016 2:25 PM, Gary Woods wrote:
On Sat, 12 Nov 2016 13:05:56 -0800, you wrote:
Does it leak through cracks or migrate through metal?
I was kinda wondering about that. Isn't H the escape artist of the
periodic table?
--
Howard L. Davidson
hl...@att.net
__
On 11/12/16 1:54 PM, Tom Van Baak wrote:
There were postings recently about OCXO ageing, or drift rates.
I've been testing a batch of TBolts for a couple of months and it provides an
interesting set of data from which to make visual answers to recent questions.
Here are three plots.
The plots
garygar...@earthlink.net said:
> I was kinda wondering about that. Isn't H the escape artist of the periodic
> table?
I think that's helium. They way they get it commercially is to start with
gas wells that have lots of it. I think some of them are 4%. Then they just
push it through quartz
Just out of curiosity, what is the age of each of these Tbolts? (i.e. date
codes?)
Thanks
- Original Message -
From: "Tom Van Baak"
To: "Discussion of precise time and frequency measurement"
Sent: Saturday, November 12, 2016 4:54 PM
Subject: [time-nuts] quartz drift rates, linear
Hi
Yes, the FE-405 uses a DDS and a cleanup. Inside the cleanup loop the DDS spurs
come
straight through. Since the FE-405 compensates for all sorts of things, the DDS
moves
around a lot. Even a one bit change on a DDS will move spurs around. With an
ever changing
DDS, you have an ever changi
So, are you measuring OCXO stability or EFC stability?
Bob
-
AE6RV.com
GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info
From: Tom Van Baak
To: Discussion of precise time and frequency measurement
Sent: Saturday
TCXO, not OCXO, but related. Sorry, but I have no graphs.
I work for a municipal radio shop. We service radios that span 20
years (through acquisitions, it was GE, Ericsson, Com-Net, M/A-COM,
Tyco, now Harris). There are several different model handhelds and
mobiles, with different designs and TCX
Hi
One would *guess* that the OCXO’s all left the factory set to center at zero
volts on the EFC. One thing
that is pretty easy to do is to look at the date code on the OCXO and the EFC
voltage. That plus the
sensitivity (one could cheat and look at the frequency rather than EFC) will
give you
On Sat, 12 Nov 2016 13:54:14 -0800
"Tom Van Baak" wrote:
> 2) attached plot: TBolt-10day-fit0-e10.gif (
> http://leapsecond.com/pages/tbolt/TBolt-10day-fit0-e10.gif )
>
> Here we zoom in by changing the Y-scale to 1e-10 per division. The X-scale
> is still 10 days. Now we can see the drift muc
On Sat, 12 Nov 2016 13:05:56 -0800, you wrote:
>Does it leak through cracks or migrate through metal?
I was kinda wondering about that. Isn't H the escape artist of the
periodic table?
--
Gary Woods O- K2AHC Public keys at home.earthlink.net/~garygarlic, or get
0x1D64A93D via keyserver
fin
Interesting, Tom. I don't think I see any of those pesky grain boundary
shifts or readjustments in the lattice structure? If I remember, these
can cause instant shifts in frequency that do not heal?
Don
On 2016-11-12 14:54, Tom Van Baak wrote:
There were postings recently about OCXO ageing, o
There were postings recently about OCXO ageing, or drift rates.
I've been testing a batch of TBolts for a couple of months and it provides an
interesting set of data from which to make visual answers to recent questions.
Here are three plots.
1) attached plot: TBolt-10day-fit0-e09.gif (
http:
I have made an experimental secondary phase noise standard, as F.Walls
would call it. In the end, it's inspired by his paper.
There is not much to it. There is a Mini Circuits PSC2-1 splitter that is
fed from an oscillator or other source. The splitter divides it into a
clean output that goes
cdel...@juno.com said:
> I just went ahead and got the short section from McMaster Carr. Want to make
> sure it's right if I'm at 400+ PSI with Hydrogen for years at a time!!!
How much hydrogen does a maser use? How big is the tank?
Does it leak through cracks or migrate through metal?
--
T
Well it's been an education!
First finding out how to identify if the Swagelok fitting is Metric by
sight and now how carefully the tubing has to be made to use compression
fittings!
I just went ahead and got the short section from McMaster Carr.
Want to make sure it's right if I'm at 400+ PSI with
Hal,
Thanks, this had me look closer at the outputs and not all RS232 chip
breakout boards shift all signals, it seems to be 4-6 lines at most.
I've seen some MAX3232 (RS232 to TTL) converters, but the better ones only
shift Rx, Tx, CTS, RTS, VCC and GND.
If I read what was suggested here ear
Compression fittings work by crushing the surface
of the tubing, and the surface of the compression
insert together to make a gas tight seal.
Stainless is very tenacious stuff, and as a result,
when it is drawn through a die when sizing it as
tubing, it gets axial ridges formed by galling, and
dam
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