Hi
They certainly aren't flooding the market these days the way they were a few
years ago. I suspect you still can get them cheap if you are willing to wait
a while. Even the two hundred dollar price is pretty good compared to the price
of a newly manufactured OCXO based GPSDO.
Bob
On Dec 3,
Hi
I went through a similar process quite a while ago. The dimensions of the
actual fountain can be quite small. One could make one the size of a shoe box
and still have it perform quite well.
Bob
On Dec 3, 2012, at 2:07 PM, Poul-Henning Kamp p...@phk.freebsd.dk wrote:
In message
We are using the SR620 to measure the interval between 1PPS signals from
two clocks. One is the Septentrio PolaRx4 GPS receiver and the other is a
Rubidium clock.
Many Thanks,
Paul
Hi Paul,
1) If you are making frequency measurements, the warm-up of the internal
oscillator is the
On 12/3/12 9:59 PM, gary wrote:
I was a bit concerned about clicking the fob for no good reason. I
assume each click is a different number. I only use it for ebay and
paypal. [Incidentally, they jacked the price from $5 to $30.]
The RSA fob doesn't have a button. It just displays a 6 digit
Indeed and it seems the 3801s have a premium above the Tbolts these days.
I have both.
I picked up the tbolt much later and I simply waited for a good deal to
show up. It took a year. I wasn't in a hurry.
But that said I am still interested in the newer versions if they are
reasonable in cost.
OK now that I am setting out to build one. Would the challenge for a
amateur be that the components you build with are basically dirty. Some how
on the copper pipe it would need to be clean and then brazed I might guess.
All of that makes for a dirty element.
To the vacuum. I used to make vaccuum
I used to work on oxygen clean systems... that cleaning is done primarily
with liquid freon (R-113 and ultrasound - may be hard to get now). The
Vacuum stuff is expensive but off the shelf. The complicated part to me is
the lasers and microwave... in addition to the super-stable oscillator you
In message CAMPhiorJihW9z6-q0+Qfd+GPLjs6e8_ovWrDxQoxV=92hgj...@mail.gmail.com
, Bill Dailey writes:
If you look at the papers on portable rubidium fountains
they are significantly bigger than a shoebox (65 cm).
Diameter is controlled by dispersion of the launched atoms (=recovery rate)
Hi
Indeed, you likely won't get USNO grade with a shoe box sized part. You can
get one to work and do quite good ADEV. No, I haven't done it, I'm just
going on what I've been told. The main point being that for a basement
project - smaller is probably lower cost.
Bob
-Original Message-
Agreed and they probably wouldn't use a cryogenic sapphire oscillator.
Sent from mobile
On Dec 4, 2012, at 8:34 AM, Bob Camp li...@rtty.us wrote:
Hi
Indeed, you likely won't get USNO grade with a shoe box sized part. You can
get one to work and do quite good ADEV. No, I haven't done it,
Basements the key. So for me bigger is better. Heck if its a rack thats ok.
It gets interesting in what types of components you can use if you are
willing to go larger.
Great point on the laser and optics. Funny thing is for small change you
can actually get used optics bench components at least
Most of the choices I've seen here mention the Tbolts, 3801, 3805, etc,
but I have never seen anyone mention the TrueTime XL-AK. It advertises 40
nsec 1 pps. Frequency as 1 x 10-12 per day. I have one and it seems to work
well but have no way to test it against anything else yet. It has four
Hi
Vacuum stuff sells by the pound (more or less). The kind you need in this
case isn't the cheap stuff. Pounds go up by the cube of the size. In this
case, I believe you want the fountain portion of the gizmo to be fairly
small.
Bob
-Original Message-
From: time-nuts-boun...@febo.com
No MIT here. Sadly.
Sent from mobile
On Dec 4, 2012, at 8:49 AM, paul swed paulsw...@gmail.com wrote:
Basements the key. So for me bigger is better. Heck if its a rack thats ok.
It gets interesting in what types of components you can use if you are
willing to go larger.
Great point on the
Al
I like the truetime products. In general easy to understand and last a long
time.
But there never seemed to be that many. Sure they were used in broadcasting
and maybe power. But the others like the 3801 and tbolt were used in telco
and mobile apps so there were 10,000s turned out and thats why
On Dec 3, 2012, at 11:27 PM, Hal Murray wrote:
li...@lazygranch.com said:
Now a phone has accurate network time, so they could get really tricky with
the time as part of the code.
Are you sure?
I don't have a smart phone, but I've heard various war stories of crappy time
keeping.
The lasers arent that difficult to make or expensive if one adopts a
modified Littrow ECDL configuration.
Laser diodes without AR coatings have been used successfully in such lasers.
Low noise current sources and close temperature control of the laser
diode chip are required.
Bruce
paul swed
Tom,
I agree. Since Paul want's to use an SR620 I presume he needs precision.
Otherwise almost any TIC with a fairly stable osc would do, for example
one with a battery backup. So I further presume that he needs nearly the
full accuracy / stability. But that's just speculation, surely Paul
I would be interested in those scripts as well. as soon as the replacement
TCXO for my sr620 arrives I can put it back together and this would be fun
to try.
-eric
On Tue, Dec 4, 2012 at 5:11 AM, Tom Van Baak t...@leapsecond.com wrote:
We are using the SR620 to measure the interval between
I agree, Bill. I do have some elk in the front yard, but they are no
help...
Don L
Bill Dailey
No MIT here. Sadly.
Sent from mobile
On Dec 4, 2012, at 8:49 AM, paul swed paulsw...@gmail.com wrote:
Basements the key. So for me bigger is better. Heck if its a rack
thats ok.
It gets
In message 50be4f1d.7020...@xtra.co.nz, Bruce Griffiths writes:
The lasers arent that difficult to make or expensive if one adopts a
modified Littrow ECDL configuration.
Laser diodes without AR coatings have been used successfully in such lasers.
Low noise current sources and close
Some RSA fobs do have a keypad. System prompts you to enter a number on keypad
and you enter the tokencode which is generated. More secure less predictable.
Or you enter a pin and token generates tokencode
Sent from my iPhone
On Dec 4, 2012, at 5:57 AM, Jim Lux jim...@earthlink.net wrote:
NTP servers. A way to hack them is to connect to one with a hostile server with
higher stratum as NTP servers are configured as 'peers'Without the md5 you
can steer a server with md5 the servers just ignore the attacking server
Sent from my iPhone
On Dec 3, 2012, at 7:00 PM, Harlan Stenn
Paul
Frankly I do not think I will live long enough to see a time nut build a
fountain Rb. Over the four years I have watched many smoke and mirror
projects with nothing coming out of is. In German we have a saying: paper is
patient. We should walk before we run.
Many members did buy a FE
I will build one right away.. but I didnt see your request. My problem is
surface mount components (the multipin or no leads)... I am not confident
in that. but I would certainly try. I am not a programmer and also
figure somebody with more soldering skills than those I have picked up
ruining
scmcgr...@gmail.com said:
NTP servers. A way to hack them is to connect to one with a hostile server
with higher stratum as NTP servers are configured as 'peers'Without the
md5 you can steer a server with md5 the servers just ignore the attacking
server
It's more complicated than that.
Hi
It's not really clear that people noticed this ….Give it a bump.
Bob
On Dec 4, 2012, at 2:33 AM, Tom Van Baak t...@leapsecond.com wrote:
Please. May we call this thread finished. It's way off topic.
Thanks,
/tvb
___
time-nuts mailing
I've just finished fitting new cells into my 5065A battery pack. A bit
of a struggle since it is quite a tight fit to re-use the original
plastic container. For information, the only cells I could find that
just about fit, and even then one has to remove the plastic covering
from them, were
Hi, I agree,
It's high time to come back to the roots!
73
Arnold, DK2WT
Am 05.12.2012 00:40, schrieb Bob Camp:
Hi
It's not really clear that people noticed this ….Give it a bump.
Bob
On Dec 4, 2012, at 2:33 AM, Tom Van Baak t...@leapsecond.com wrote:
Please. May we call this thread
Hi
A few kilometers of optical fiber should do the trick. Servo the fiber
temperature to keep things locked up.
Bob
On Dec 4, 2012, at 4:17 PM, Poul-Henning Kamp p...@phk.freebsd.dk wrote:
In message 50be4f1d.7020...@xtra.co.nz, Bruce Griffiths writes:
The lasers arent that
Hi
I would guess that HP/Agilent/Symmetricom and Trimble made 100X more GPSDO's
than the next five people in the business combined over the 1995 to 2005 period.
Bob
On Dec 4, 2012, at 10:26 AM, paul swed paulsw...@gmail.com wrote:
Al
I like the truetime products. In general easy to
CDMA requires accurate time information in the air interface as part of
the low level protocol.
From the standards documents I have read, and the BTS devices I
personally have had exposure to, this always comes from GPS.
The air interface for CDMA also includes a local time offset that is
Hi
My 8th grade science project was made from optical bits from the MIT flea. One
of the criticism's of the project was that it could have been better if I'd
just shopped a bit harder….
What ever it is you need - it'll be gone when you need it.
Bob
On Dec 4, 2012, at 10:05 AM, Bill Dailey
Hi
But would you cryo cool the walls of the fountain enclosure? It helps …..
Bob
On Dec 4, 2012, at 9:46 AM, Bill Dailey docdai...@gmail.com wrote:
Agreed and they probably wouldn't use a cryogenic sapphire oscillator.
Sent from mobile
On Dec 4, 2012, at 8:34 AM, Bob Camp li...@rtty.us
Sorry about this, Tom, but there's some misinformation here.
I wasn't reading this until I saw your posting.
-Original Message-
From: Jim Lux
Sent: Tuesday, December 04, 2012 7:58 AM
On 12/3/12 9:59 PM, gary wrote:
I was meditating a bit on the power grid synchronization. If all the
On 12/4/2012 3:51 PM, Bob Camp wrote:
Hi
How much backup time does that battery pack give you?
Bob
Bob, it's at least what they claim in the manual for that Option,
something like fifteen minutes from what I remember.
Dan
___
time-nuts mailing
Hi
Based on a quick look, the SkyNav does not appear to be a timing specific part.
A 2 us error in a navigation part would come as a big surprise.
Bob
On Dec 3, 2012, at 11:12 PM, Gabs Ricalde gsrica...@gmail.com wrote:
I'm using a Symmetricom 58534A GPS timing receiver and a GPS board
Hi
So roughly what a simple UPS would give you.
Bob
On Dec 4, 2012, at 7:34 PM, Dan Rae dan...@verizon.net wrote:
On 12/4/2012 3:51 PM, Bob Camp wrote:
Hi
How much backup time does that battery pack give you?
Bob
Bob, it's at least what they claim in the manual for that Option,
In a message dated 12/4/2012 6:10:36 P.M. Eastern Standard Time,
docdai...@gmail.com writes:
I will build one right away.. but I didnt see your request. My problem is
surface mount components (the multipin or no leads)... I am not confident
in that. but I would certainly try. I am
But thats not HP. :-)
I would agree that a external ups would be about the same price and for
some of them you can slightly increase the battery size. There are a lot of
surplus ones out there for a very few dollars. Shippings normally the
bigger cost these days.
Regards
Paul.
On Tue, Dec 4, 2012
With the price of T-Bolts now higher, does it make sense to build your own
GPSDO?
What is the simplest phase detecter that could work? I think only that,
and then a duouble oven crystal from eBay, a GPS and and Arduido.
Yes the Aruino is expensive compared to a bare uP chip but using one, I
Is it really off topic? Actually I think it is very boring to talk about
people comparing one 10MHz reference to some other 10MHz refeerence without
ever putting either of them to practical use.
But the question of if it is even possable to spoof time is certainly
related to time keeping, has
On 12/4/12 4:28 PM, Bill Hawkins wrote:
Sorry about this, Tom, but there's some misinformation here.
I wasn't reading this until I saw your posting.
-Original Message-
From: Jim Lux
Sent: Tuesday, December 04, 2012 7:58 AM
On 12/3/12 9:59 PM, gary wrote:
I was meditating a bit on the
Hi
Based on a quick look, the SkyNav does not appear to be a timing specific
part. A 2 us error in a navigation part would come as a big surprise.
Bob
==
Indeed! The PPS output of various navigation parts I've checked recently
have typically been
albertson.ch...@gmail.com said:
What is the simplest phase detecter that could work? I think only that, and
then a duouble oven crystal from eBay, a GPS and and Arduido.
You also need a good D2A to drive the EFC on the osc.
Yes the Aruino is expensive compared to a bare uP chip but using
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