I agree; regular input from the outside. Here's what I do: 1) I have a
Casio wristwatch with WaveCeptor to set its time every morning, and it is
set to beep on the hour. It produces two beeps. It has never been off by
more than about 500ms against my Thunderbolt running Lady Heather. 2) I
have an A
The second harmonic is -36 dBm, the third 43, and the 10 MHz signal is
consistently around 7.6, so I think I am good to go.
This is a nice little unit for the money.
Thanks also for the various mounting suggestions. I may decide to mount
the MV89 on stand-offs on the base of the old Ovenaire
Hi
Never seen that problem, but it sounds very much like a relay / mux problem in
the ohms section.
Bob
On May 17, 2013, at 9:23 PM, Volker Esper wrote:
>
> Hi,
>
> I bought a 34401A lately. It's all fine, except it's got a fault when
> measuring low ohm with 2-wires: the value runs (monot
Hi,
I bought a 34401A lately. It's all fine, except it's got a fault when
measuring low ohm with 2-wires: the value runs (monotonic) from 0 to 30
oder 40 Ohms at a speed of say 1 ohm per second and after a while it
decides to run back... When using 4-wires-measurement everything's alright.
Hi
If you have about 7 dbm and the second harmonic is down > 20 db I'd say your
unit is ok and move on.
Bob
On May 17, 2013, at 8:09 PM, Frederick Bray wrote:
> Hi Bob,
>
> Yes, I did notice the prior thread about this. At the moment, I have been
> looking at it using the spectrum analyzer
I occasionally have the same issue when receiving microwave counters that (for
some strange reason) are equipped with poor TCXOs and need to install an OCXO.
To solve this problem, I found a source of bare FR4 glass epoxy board stock:
http://accurateplastics.thomasnet.com/viewitems/epoxyglas-g1
Hi Bob,
Yes, I did notice the prior thread about this. At the moment, I have
been looking at it using the spectrum analyzer function of my HP 8935.
With the reference level set to 20 dBm, I am getting a reading that
varies from 6.99 to 7.37. I am trying to figure out whether this is
norma
Hi
The big question is weather yours has the "capacitor of death" problem or not.
If it has the bum capacitor(s) in it, you will need to pop it open and replace
the cap. I would check things out before moving forward.
Bob
On May 17, 2013, at 4:19 PM, Frederick Bray wrote:
> I just received m
Hi
Given the temperature coefficient of the device, performance is going to be
very dependent on correcting it for the local thermal environment. That may or
may not be practical in this case. Correcting it and then moving it probably
isn't going to work very well.
Bob
On May 17, 2013, at 6:3
Right, that's why I brought up the GPS sentences. You'd need a small micro
to read the chronodot registers and output formatted serial, the 1pps can
go directly to the PC.
On Fri, May 17, 2013 at 3:24 PM, mike cook wrote:
>
>
>
> Le 17 mai 2013 à 22:52, Eric Williams a écrit :
>
> > That's bas
Le 17 mai 2013 à 22:52, Eric Williams a écrit :
> That's based on my experience, but I did go in and tweaked the offset
> register in mine over the course of a month or so. I think it has gotten
> off 3-4 seconds in a year.
>
I have found the same, BUT, they are not a solution to the issue.
That's based on my experience, but I did go in and tweaked the offset
register in mine over the course of a month or so. I think it has gotten
off 3-4 seconds in a year.
On Fri, May 17, 2013 at 1:33 PM, Tom Van Baak wrote:
> > Even something as simple as a Chronodot will hold to a few seconds
> Even something as simple as a Chronodot will hold to a few seconds a year.
Eric,
Are you sure? My understanding is that the Chronodot is based on the DS3231.
Quoting http://datasheets.maxim-ic.com/en/ds/DS3231.pdf we read:
The DS3231 is a serial RTC driven by a temperature compensated 32k
I just received my first Morion MV89A. It came attached to a piece of
the original PC board.
I wonder how others have mounted theirs. One option seems to be to get
a piece perf board (perhaps with solder pads). Another might be to
leave it on the original PC board since that seems to have a
My reading was that in the past he was happy to be within a few seconds but
now wants something better. I'm not 100% sure. But yes a wristwatch is
good enough for a few seconds. Periodically the user could check his
watch against an NTP connected computer outside the room.
In general there ar
Even something as simple as a Chronodot will hold to a few seconds a year.
Make something out of an ocxo and you can beat that. You just need to
transfer time in from some outside source once a year or so to synchronize
it. Make your gizmo output GPS time sentences and most NTP implementations
s
Hi
I believe the original spec on this was "accurate to a few seconds". If that's
still the case (I have been known to miss zigs and zags in threads …) the sync
requirement isn't terribly stringent. A wrist watch and some care can get you
to a fraction of a second.
Bob
On May 17, 2013, at 12:
Hi.
Re the setting issue I'd look for a solution that can be initially synchronized
from the 1pps pulse from a GPS receiver or other precision source.
If you search for prior posts from me over the last several weeks you should be
able to find one where I expand on this in a bit more de
If there is no way to get radio signal into the room, then buy a rubidium
oscillator. Conect the Rb to a small notebook PC the run Linux or BSD
Unix. Let the Rb oscillator drive NTP and get it sync'd up outside your
room and then walk the Rb/NTP server into the room.Because you are
isolated
On 5/17/13 5:07 AM, Grant Hodgson wrote:
A client company has sourced a quantity of 'New in Box' iSBC series
memory modules manufactured by Intel in the 1980s for a MULTIBUS based
computer system. These are still in their original, sealed packaging and
have been stored (for 25 years) in controlle
Hi
The DRAM's (and some cpu's) of that era were not as well specified for clock
timing as the parts we have today. It's a matter of degree, but it was much
worse back then. I would worry less about frequency than about duty cycle. In
this case with a binary divide, the duty cycle on the clock s
Hi
There is one little thing that I did forget:
Were the packages ever dropped? Are they padded well enough that a drop would
not generate much of a shock pulse? The concern is the ~ 1,000 G 1/2 ms type
pulse you would get from a drop onto a hard surface.
Oscillators in service in this kind o
Grant on the purest of speculation. Most likely not. Yes the xtal ages but
as you say the frequency is not critical. Though that actually may not be a
true statement. How far is to far for the dram timing? The other thing that
most likely is not an issue is a variable cap. Most likely it never had
Hi
There are some pretty good papers on system reliability as parts age. Most of
what I have read assumes the system is operating, and that failed parts get
replaced. In the sense of those papers, crystal oscillators are not like fan
bearings. There is no guarantee of an ultimate end of life we
Usually aged crystals are reliable.
On Fri, May 17, 2013 at 2:07 PM, Grant Hodgson
wrote:
> A client company has sourced a quantity of 'New in Box' iSBC series memory
> modules manufactured by Intel in the 1980s for a MULTIBUS based computer
> system. These are still in their original, sealed pac
Hi
The target design lifetime of your typical clock oscillator is in the 10 to 20
year range. These parts are well past their intended replacement date.
Things like package leak rates, and epoxy issues do indeed kill oscillators.
Both are a time dependent thing and are not particularly depende
A client company has sourced a quantity of 'New in Box' iSBC series
memory modules manufactured by Intel in the 1980s for a MULTIBUS based
computer system. These are still in their original, sealed packaging
and have been stored (for 25 years) in controlled conditions. These
cards are requi
Hi
Rather than getting uber crazy, how about something simple:
Take a cheap telecom Rb from the usual auction sites. Get it running and on
frequency. Probably hook a battery into the power supply for backup. Run it's
pps into the PC.
At this point you should (with some luck temperature wise) b
If you can't get GPS signals 'inside' but you can get GSM coverage, site
screening can't be all that good, so rebroadcasting the data from an
external GPS receiver signal might be the best option. Just pick a transmit
frequency and power combination that also provides coverage 'inside'- with
d
Le 17 mai 2013 à 06:45, Grant Waldram a écrit :
> This is inside a security-fob protected room. I
> can't get GPS signals in there, and the Australian radio clock network was
> shut down about ten years ago. Our CDMA network was turned off in 2008.
> Right now all I can think of is GSM, and whi
If a phone line is available and you can stomach the small cost of a
long distance phone call now and then, it seems like ACTS would be the
simplest route. Several countries still maintain ACTS services;
Australia's NMI lists a number that they say is not functional, but it
does pick up with a mode
Moin,
On Fri, 17 May 2013 14:45:09 +1000
"Grant Waldram" wrote:
>
> I've not had much need for time synchronisation over the years, but in
> recent years NTP has been able to get me by. Unfortunately I'm now faced
> with a network that needs a moderately correct clock (I'm scared of using
> th
Hi folks. I wouldn't call myself a time nut, so this is really an effort to
ask for advice from some people who know the field. My first contact with
time synchronisation was looking at the instrumentation clocks for the
Woomera rocket test facility when I went out there for a few (large!) hobby
ro
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