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-nuts
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 microsecond
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 VP
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
___
time-nuts mailing
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
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
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
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:
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's see if it shows up
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 not optimal,
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.
Beware
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
units
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
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
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 Alberto I2PHD
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
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
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 that,
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 does
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
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-en.htm
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 called by a C
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
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 IC,
thermally coupled with the back
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
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
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
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