Brooke Clarke wrote:
> Hi Alberto:
>
> I don't think so. The crystal oscillator is aging and so the EFC value
> should match the aging in the long run. See that plots at:
> http://www.rt66.com/%7Eshera/index_fs.htm
>
> To see of a GPSDO is working compare it's 1 PPS output to the GPS 1 PPS.
>
Didier Juges wrote:
> --- snip ---
> The question that comes up is: how do I know my GPSDSO is working and
> how do I evaluate its stability?
> --- snip ---
Couldn't you plot the EFC value vs time, and check whether it tends
asymptotically towards a (pseudo-)stable value ?
Knowing the Hz/V para
Hal Murray wrote:
>
> Does Heisenberg get involved? If so, how far are we from being able to
> notice it?
> How would a timekeeper state the basic idea?
> I'm fishing for something like "If you know the time you don't know where
> you are."
>
The "observable" paired with time is Energy, n
Arnold Tibus wrote:
> Unfortunately there is only the hex list of the pic code.
> As I would like to experiment as well with this modification
> and try to change some parameters to fit my LPRO
> and some different OCXOs I own,
> is there a way to get the commented source code of it?
>
I de
Tom Van Baak wrote:
>
> I'm curious about the 10 kHz signal. Can you send
> me a pointer to it? Usually 1 Hz is good enough and
> in practice most GPSDO use an averaging algorithm
> that is more akin to 0.01 Hz to 0.001 Hz.
http://gpsdo.i2phd.com/
73 Alberto I2PHD
___
Arnold Tibus wrote:
> Hello,
> perhaps of general interest:
> I found an intersting note via "GPS-world", new for me,
> but perhaps already well known,
>
> telling that the Motorola M12+ is now replaced
> by an improved version, the CW12 from Navsync.
> ("Designed as a functionally equivalent
David Forbes wrote:
>
> The result is a wiggly line on a graph, which is what most radio
> astronomy results look like.
>
So in the movie Contact they were right when saying that very few,
if any, radio astronomers actually "listen" to what is received...
73 Alberto I2PHD
_
>
> To my knowledge, nobody tunes the frequency of the oscillator in their GPS
> receiver.
>
> Matt
>
As far as I know, the Trimble Thunderbolt uses the same 10MHz OCXO
that it disciplines as clock for the GPS receiver.
73 Alberto I2PHD
___
time-n
Magnus Danielson wrote:
>
>>I looked in my data and their spec sheet shows +/- 1 microsecond. But,
>>I beleive this was much better than that. I cannot find it, but I
>>beleive I seen a report where somebody compared the Jupiter and it was
>>in the 120 to 150 nanosecond class.
>
>
> +/- 1 m
Poul-Henning Kamp wrote:
>
> You need to time the 1PPS signal to get the precise time, the
> serial timecode alone, NMEA or not, doesn't do it.
>
Does anybody have reliable data on the jitter present on the 1pps signal
of the Rockwell/Navman GPS boards ?
I used in the past a 8-channel Motorola V
How do the two compare? Having already a Z3801A would it worthwhile
to try to get hold of a Z3816A ? In other words, how does the MTI
OCXO used in the Z3816A compare with the 10811-60158 of the Z3801A ?
Thanks
Alberto, I2PHD
___
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Richard,
thanks for your answer. I got my OCXO134-12 from eBay (NOS), and so far I
have been unable to find its exact specs, as it is not reported on the
Isotemp Web site (only the -10 is there). An email to them remained without
answer, of course... probably it was a special build for some t
Bill Hawkins wrote:
Speaking as a process control engineer, it sounds like
too much gain. You can verify that it is the oven by
warming up the device somehow. That should change the
period of oscillation. If it is still 7 minutes then
reduce the gain somehow.
I can't reduce the gain of the te
Richard H McCorkle wrote:
[snip]
In interfacing an Isotemp mil spec version of the HP 10811B with a
sensitivity of 9.7e-9/volt and a span of 4.85e-8 to the Shera controller
even with [snip]
Richard,
do you perhaps have any experience of using the Isotemp OCXO134-12 unit ?
I built a GPSDO
Stephan Sandenbergh wrote:
I wondered if anyone could help me with an interfacing problem? I guess
that it is a trivial question to those that know, but I am rather
puzzled by it.
My very stable OCXO output a 8dBm (50ohm) sine wave. How is this signal
converted/interfaced to a logic standar
Just for the sake of curiosity and to end this topic, I measured the
accuracy of another sound card I have in my PC, a Terratec Aureon Sky. A
good card, but not of the same class of the Delta 44. But it was more
accurate... 40001.5 Hz which translates into an error of 37.5 +- 2.5 ppm
73 Alberto
Ulrich Bangert wrote:
>Because it is a differential measurement between the two channels (which
>are sampled exactly the same time due to the adc hardware) the first
>idea was, that the effects introduced by the not so good sample clock of
>a ordinary sound card may cancel out completely.
>
>
B
>>The list is set to convert HTML to plain text. That's what Mailman
>>defaults to on setup, but I pretty strongly agree with that approach, so
>>left it as is.
>>
>>
>
>Yes please, no HTML if we can avoid it.
>
>
HTML is of course a vehicle of infections and the use of net resources
is n
Alberto di Bene wrote:
> P.S. Let me please test how this reflector behaves when sending HTML
> messages... I have noticed a strange behavior in the past... it
> insists on reformatting
> the HTML message at its will...
> Here following there should be an image... let&#x
I have measured the accuracy of the time base of my M-Audio Delta 44
sound card with the tolerance (and the accuracy) of 2.5 ppm
I modified my program TCube for a sampling rate of 96 kHz, and set it
for 40 kHz output.
I connected the output to my 5328B (whose time base is driven by
Alberto di Bene wrote:
>I am fearing that finding drivers for this card won't be that easy...
>
>
I was wrong ! I have just found the drivers here :
http://www.cec488.com/gpibupgd.html
A free download... now the quest for the ISA PC can start... :-)
73
> An old PC is probably your best bet.
Before I start hunting for an old PC with an ISA slot, does anybody know
if Capital Equipment Corporation (the maker of my ISA GPIB card) is
still in business ?
I am fearing that finding drivers for this card won't be that easy...
73 Alberto I2PHD
David Kirkby wrote:
> If your PC has an ISA slot, or you have an older PC with an ISA slot,
> then a GPIB board is not that expensive on eBay. Just save yourself a
> lot of hassle and get one from National Instruments, as they are
> better supported than other makes.
I have an ISA GPIB card colle
Tom Van Baak wrote:
>I measured the phase, frequency and Allan deviation of
>the sound card on my cheap PC. You'll enjoy the results:
>
>http://www.leapsecond.com/pages/sound-1pps/
>
>If any of you with a high-end sound card want to repeat
>the experiment let me know.
>
>
>
Unfortunately, while
Chuck Harris wrote:
> A 10% variation in line frequency would cause a 10% variation in power
> consumption registered. Induction type power meters will remain accurate
> with a 10% variation in power line voltage, however.
>
> Someday, our utilities will convert all of our meters to solidstate
>
John Ackermann N8UR wrote:
>One thing I want to explore is how difficult it would be to provide an
>external clock for the Delta 44. Higher-end boards in the M-Audio
>series have a "wordclock" input, and I suspect that the Delta 44 PC
>board may be hackable to enable that.
>
>
If you succeed in
Chuck Harris wrote:
> Let's see, your graph shows for that small time interval that the
> frequency
> is within 0.05% of being correct. If it continued at that rate of error,
> it would result in an error of about 42 seconds in 24 hours.Sounds
> pretty
> bad, until you factor in a few other v
FWIW, this is a plot of the 53rd harmonic of the 50 Hz of the mains at
my house, measured not more than half a hour ago. Nominally it should be
50 x 53 = 2650 Hz, but it ain't...
http://sundry.i2phd.com/mains.html
73 Alberto I2PHD
___
time-nuts mai
>Have you checked high precision quartz watch mouvements? Longines, a Swiss
>watch manufacturer, uses a quartz mouvement called "Calibre L546" with +/- 10
>seconds per year accuracy. It runs for 10 years (!) on a watch-size Lithium
>battery.
>
>
>
Apparently also Tissot has something similar.
Things went faster than anticipated. Marco IK1ODO had already a PDF of
the Service Manual of the General Technology rubidium standard and sent
it to me. He said that the source was again John Ackermann N8UR
So I placed it in a publicly accessible Web site for all to download.
You can find it here :
John Ackermann N8UR wrote:
>Alberto --
>
>How about you scan the manual and return it to me? Extra karma if you
>make the scan available online.
>
>73,
>John
>
>
>
John,
ok, I will send you in a private message my shipping address. I will
scan it and prepare a PDF file (which my scanner
John Ackermann N8UR wrote:
>Alberto, I just got home and checked -- I do have the manual for the
>304B. Now what?
>
>John
>
>
John,
if you are ok with departing from it (i.e. you don't need it anymore),
I am willing to pay the price you will ask for it and the shipping
expenses .
Just let me
I have placed a few pictures of my old (circa 1972) Rubidium standard at
this URL :
http://www.i2phd.com/rubidium.html
hoping that someone has some information about it, maybe a Service Manual...
It locks. It takes about 40 - 45 minutes to do it, but then it locks
TNX
Alberto, I2PHD
_
Mike Seguin wrote:
>Alberto,
>
>This site has much information on the engines. It lists the following, which
>doesn't say Navman, but the model number is in the series
>
>Datasheet Jupiter GPS Receiver TU30-D140-211/221/231. size 1.3MB, 19 pages,
>date: sept. 1998
>
>http://www.gpskit.nl/downloads
Does anybody have, or know where to find, the specifications
of the Navman TU30-D165 GPS board ?
Neither Google nor the Navman site are of any help.
Thanks
Alberto I2PHD
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Tom Clark wrote:
> I built a 10 MHz locker using the Jupiter-T and TvB's PIC-based
> synchronous counter with the idea that the 10 kHz jitter could be
> averaged out.
>
>
A very simple GPSDO using the 10 kHz output of the Jupiter-T is
described here :
http://gpsdo.i2phd.com/
73 Alberto
>>DOS timekeeping is restricted to the 18.2Hz i8254 counter and that
>>is far to crude for the NTP algorithms.
>>
>>A few SNTP tools work and their precision is obviously 18.2Hz...
>>
>>
In case somebody needs it, many years ago I wrote a simple asm routine,
meant to be run under DOS and calle
Chuck Harris wrote:
> Alberto di Bene wrote:
>
>> Does anybody know what the HP 59307A uses ? It can switch from DC to 500
>> MHz and the measured DC resistance is on the order of 0.2 ohm. Looking
>> into the unit reveals that the switching device is shaped like a fat
Brooke Clarke wrote:
> A PIN diode is great for switching RF frequencies above the diode's
lifetime. But not so good at switching DC coupled signals.
> The FET type switches, like the MAX458 are designed for switching DC
coupled signals.
Does anybody know what the HP 59307A uses ? It can switch
Ulrich Bangert wrote:
>What i
>have played around with in the last days is a 32 bit risc controller
>similar a ppc405 in form of a ip core inside a gate array. That would
>lead to kind of SOC solution for the problem and is a interesting
>alternative. Any comments on this?
>
>
My purely personal
Dave Carlson wrote:
[...]
I can't say where that strange "A03912" number came from, except that it may
have been a separate asset number added to that oscillator by the previous
owner or that as a result of a previous repair a new label was generated as
a replacement and the prefix was not con
How are the 10811 OCXOs serially numbered ?
I ask this, because from a photo on eBay I saw a 10811-60111 with
serial number 2850A47273, a rather long number. The 10811-60111 in my
5328 counter has as S/N the number A03912, which looks like it belongs
to a different numbering scheme.
I don't know if this message with a picture embedded will
make it through the reflector, but anyway this is the pinout
of the Isotemp I used for my own GPSDO :
73 Alberto I2PHD
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Daun Yeagley wrote:
Hi Alberto
The right-click method works if you are reading in a browser (I just tried it
using SquirrelMail). However, I couldn't do that using LookOut (OutLook).
Fortunately, Rex's method also works, so there are at least two ways to
circumvent the problem.
H, then it de
Rex wrote:
I then tried to go up one level so that I could point to the link and
say "save link as". Unfortunately this site wouldn't allow access to the
parent level. If possible, future posters could help the situation if
acess was allowed to both the file and its home directory.
Rex,
you don
Bill Janssen wrote:
Thanks to everyone that responded I now have more than enough to
check this oscillator to see if it is OK for my use.
In case you, or anybody else, need the complete Operating and Service
Manual of the 10811A/B, I have uploaded it to one of my Web sites. It is
rather large, 75
David Kirkby wrote:
4) Feed the other output from the power splitter into the LO port of
a mixer, via a cable that is a odd integer multiple of a quarter wave
Why an odd multiple of a quarter wave ? Wouldn't an even multiple be
more adequate, so that
the input impedance is reflected more or less
That's a good hypothesis, but given how long this system (same
receiver and antenna) has been running without ever encountering
something like this makes me doubt it's a GPS anomaly, or at least
a local one. A long history has shown that this receiver/antenna
very seldom
I used Unix between 1983 and 1993, but now it is a withered skill
that is not supported by any Unix operating system. I can download
the .gz files, but I can't open them with WinZip. Is this a version
problem, requiring a newer version of WinZip than 1998? Seems to me
that WinZip could open a tar
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