Hi,
I am a newbie to this list. I have downloaded the archives and read about
5,000 of the past messages. I plan on building my own GPSDO, probably using a
LEA-6T (but LEA-7T or LEA-M8T would be good if I can find one affordably). I
have a MTI 260 on order (although it could wind up being a 261
Hi,
Wrote: Since the front end chips are mixed signal ASIC’s, it will take more
than a bit of time to replace them directly. Re-doing the entire front panel
board is the most likely way to “fix”the problem. The question is - why do that
at all? Just do a PC instrument that does the same thing
> I'm thinking of trying a new GPS board next.
A bad GPS board won't prevent communication to the main CPU.
You might try capturing the output when you power it on. It sends out
something. I forget what, probably the ID string.. If that doesn't work,
try a scope. You might have the PC
Actually not hard to do... lay out circuit board (free version of Eagle),
have boards fab'd at Oshpark.com or your favorite Chinese proto shop (I like
gojgo.com). Have solder paste stencil made at oshstencils.com. Squeege
solder paste down with a credit card. Place components by hand.
Fellow time-nuts,
Over a year and a half or so, we have been starting to grasp the various
aspects of the cross-correlation catastrophe. This consists of two
properties, one is the insertion of anti-correlated noise into the two
channels, and then when cross-correlated it produced a
Hi
> On Jan 25, 2016, at 8:36 PM, Gerhard Hoffmann wrote:
>
> Am 25.01.2016 um 18:20 schrieb Graham / KE9H:
>> There are clock distribution parts designed to do this low noise frequency
>> conversion and distribution.
>>
>> Consider TI LMK04100
>>
>>
>> 150 fs class
Hi Bert,
I have noticed that if I have the right magnification,
I can do amazing things. Even the tiny age related
tremors that naturally occur in my hands reduce with
magnification. The brain is a marvelous servo mechanism.
Get a good 40x-80x zoom stereo microscope meant for
dissection, the
John
I am no expert but I have been playing ( A lot) with my Z3801 during the
last month, after having it in storage for 15 years !
What software program are you running, under what operating system?
Can you see the satellites being tracked in the receiver status window
in SATSTAT? on the
John
The 3801s are getting very old at this point. I know mine has started to
show a loss of lock occasionally on the oscillator. Intermittent problems
are very tough.
What jumps out to me is the 27 volts. That seems low as I recall. I run at
48 V. I understand there were several models made so
> Hi
> I have a OCXO marked Schlumberger Adret 622 used in Adret 4101A Frequency
> standard receiver
> I do not know if it is similar but performance seem OK
> It is a cube of about 70 mm with DB9 output connector ; frequency is 5MHz
> with external pot adj.
> The ADEV seem good: data here
>
Hi everyone,
Has anyone else seen GPS time jump by -13.7 usec today?
I just heard from several geographically quite distributed radio
observatories that they have seen their GPS receiver(s) jump compared to
their in-house standards.
Regards, Paul Boven.
Chuck
Thank you for your advice, I will print it out and when needed experiment.
We use SMD.s and two of our tem members are very good at it, I do limited
stuff and have some tools but also a macular hole in one eye. In designs I
try to stay with solder able SMD's and we have projects like
On 1/26/2016 12:54 AM, Hal Murray wrote:
I'm thinking of trying a new GPS board next.
A bad GPS board won't prevent communication to the main CPU.
You might try capturing the output when you power it on. It sends out
something. I forget what, probably the ID string.. If that doesn't work,
there are two versions a 24V version and a 48V version ... If you look
at the back of the Z3801 there will be a "dot" on which voltage your
unit is powered for . ...The 48V version is the more common. Since your
unit is going through the full LED cycle on 27V supply I suspect that
you do have
John wrote:
I even left it on over night.
It may need longer than overnight to assemble an almanac and
initialize everything. Leave it on for a week before you panic.
Best regards,
Charles
___
time-nuts mailing list -- time-nuts@febo.com
To
Indeed, multiple Z3801A GPSCON pages show an impulse step for by the amount
you describe. I would describe the graphs as showing a positive TI step
followed by negative TI step. My reading of the graphs shows that it is
consistent with the 13.7 usec you describe.
Am attempting to attach some
Good comment on leaving it on for a long time if the almanac has been lost.
You see nothing accept the green pwr led and I have seen 48 hours to lock.
I added a batter 2 X AA and that keeps the almanac and enhances startup.
But nothing like a modern 30 sec or less receiver.
WB8TSL
On Tue, Jan 26,
On Tue, 26 Jan 2016 16:12:41 +0100
Paul Boven wrote:
> Has anyone else seen GPS time jump by -13.7 usec today?
> I just heard from several geographically quite distributed radio
> observatories that they have seen their GPS receiver(s) jump compared to
> their in-house
Paul,
I've received inquires about the 13 us jump since 8 PM last night (PST).
Possibly related: http://www.navcen.uscg.gov/?Do=gpsShowNanu=2016008
Check your logs to see if your receiver is using SVN23/PRN32.
/tvb
- Original Message -
From: "Paul Boven"
To:
In message <56a78ce9.20...@xs4all.nl>, Paul Boven writes:
>Has anyone else seen GPS time jump by -13.7 usec today?
>I just heard from several geographically quite distributed radio
>observatories that they have seen their GPS receiver(s) jump compared to
>their in-house standards.
The GPSCon "International Z3801A web plot" page is still active:
http://www.realhamradio.com/GPS_websites_list.htm
Most of the entries are stale but here's a few that show the recent glitch
nicely:
http://www.shaunmerrigan.info/timeandfreq/gpscon/gpsstat.htm
At 09:12 AM 1/26/2016, Paul Boven wrote:
Has anyone else seen GPS time jump by -13.7 usec today?
My tbolt locked ntp server saw an unusual spike of about that
magnitude just after 00:00 1-26-2016 UTC. (The bump at 4 seconds
is from the daily backup run.)
--
newell N5TNL
One last post on this off topic subject: Eyes.
The younger folk will think eye problems amount to near
or farsightedness... maybe a little astigmatism. The
slightly older folk (37+) will know about presbyopia...
the loss of your close working focus... your arms get
shorter.
Then there are the
Thanks guys. I'll hook it up to the regular power supply and let it cook
for a while. I have a uBlox board I want to check for jitter, but I'll need
that '3801 to check it against. The fun part will just have to wait.
___
time-nuts mailing list --
Hello list !
I have a HP 58503A who worked fine for two years.
After a short power cut, it does not lock on GPS. I tried some commandsn
including :SYST:PRESET but nothing works
Here's a :SYSTEM:STATUS ? after the PRESET and after waiting a few hours :
---
Tom
This is what I sent unchecked Rich Text (HTML) now
Has anyone noticed GPS problems today?
It looks like PRN32 / SVN 23 went faulty yesterday and was taken out of service
last night at 22:00 ZULU
http://www.navcen.uscg.gov/?Do=gpsShowNanu=2016008
We've seen issues with a number of
Jim,
3) Input and output level (?)
the oscillator is a HCMOS output, so figure swinging about 3.5V
Any multiplier configuration will produce lots of different harmonics, and will
need fairly serious filtering after it if you want a clean 100MHz.
If you have a 20MHz oscillator with
Here's what my Z3801A saw using Z38XX. 00:00 on the graph = 06:00 UTC.
My location is ~N50, W104. I don't know what SVNs were used. I'm not
logging that data.
Ed
On 2016-01-26 11:00 AM, time-nuts-requ...@febo.com wrote:
Message: 3
Date: Tue, 26 Jan 2016 16:12:41 +0100
From: Paul Boven
I have been working on a compact portable 10Mhz bench standard
using both an FE FE5680A Rb oscillator and an Oscilloquartz ovenized
crystal oscillator. I was curious to see how their short and long term
stability
would work out, and I needed something to drive my 6502 amp to pipe the signal
to
Hi,
It seems that several SVNs (PRN 2, 6, 7, 9 and 23) got feed bad data.
This is not the first instance, it seems that single SVNs have had bad
data the last couple of days.
When our 4 GPS receivers at work got "hit" at midnight, it got our
attention. Interestingly enough they did not
Walter that OCXO sure looks odd I would expect unfiltered to be a lot
better then that. I would guess that several possibilities exist.
The actual crystal is a 5 MHz and it feeds a doubler.
The chain has something thats gone non-linear. -5dbm seems low to me.
Oscilloquartz have a very fine
Chuck, what do you use for a hot air source. The good ones are very expensive.
Wonder if there is something for the hobbyist. Have seen a few repair videos
where they used just used a hot air stripper.
I had to yank a couple SMD resistors off a board the other day and had to use
two soldering
On 1/26/2016 11:52 AM, walter shawlee 2 wrote:
I have been working on a compact portable 10Mhz bench standard
using both an FE FE5680A Rb oscillator and an Oscilloquartz ovenized
It is important for a 10 MHz source to launch a pure sine wave
and also to have an accurate 50 ohm impedance at
Moin,
On Sun, 17 Jan 2016 17:32:58 +0100
Gerhard Hoffmann wrote:
> BTW the extra quiet reference of the LT3042 is a current source, so
> there is no real justification for the repeated claims here that ECL
> must be noisy because of its integrated current source.
I had a
About 10 years ago I demonstrated a Hot Air Reflow method that is simple
and needs no exotic tools and no heroic skills to solder surface mount
devices. I also supply the solder paste in a syringe with a modified
needle. The paste is Kester Easy Profile 256.
You can see my method at:
Paul Boven wrote:
> Hi everyone,
>
> Has anyone else seen GPS time jump by -13.7 usec today?
> I just heard from several geographically quite distributed radio
> observatories that they have seen their GPS receiver(s) jump compared to
> their in-house standards.
We were able to track this down
Hi
If your OCXO is putting out less than 0 dbm, it’s broke. Given the way these
parts are treated
in the salvage loop, damage is not unusual. There are a *lot* of examples of
surplus OCXO’s
with low output. Normally it’s a damaged output cap or something like it. I’ve
seen roughly half the
Hi,
On 01/26/2016 11:46 PM, Martin Burnicki wrote:
Paul Boven wrote:
Hi everyone,
Has anyone else seen GPS time jump by -13.7 usec today?
I just heard from several geographically quite distributed radio
observatories that they have seen their GPS receiver(s) jump compared to
their in-house
Slashdot got it.
http://it.slashdot.org/story/16/01/26/1735223/discrepancy-detected-in-gps-time
On 01/26/2016 12:20 PM, Scott Newell wrote:
> At 09:12 AM 1/26/2016, Paul Boven wrote:
>
>> Has anyone else seen GPS time jump by -13.7 usec today?
>
> My tbolt locked ntp server saw an unusual spike
Magnus wrote:
Interestingly enough they did not experience issues at the same
time, it just started about the same time.
Presumably, each rx would be affected when it added one or more
corrupted satellites to the constellation it was using for its
solution. Since each rx makes those
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