Like many of us, I find my best bargains on eBay.
I happened to be searching for MHz DIP oscillators and ran across this item:
http://www.ebay.com/itm/151957504565
No replies necessary. If you are the lucky winner ("only 1 left"), please
contact me, off-list ;-)
/tvb
My T-bolt is running on a Power-one International Series HCAS-60W-A supply,
hefty enough to run at least 4 more. Ripple and noise measure less than 100
micro-volts peak-to-peak. The T-bolt seems quite happy.
Jeremy
On Sunday, February 28, 2016, Dave M wrote:
> Pete
While in the navy, I had to repair a hp cesium standard.
The control circuit had the oscillator slewed to one limit, I do not
remember whether high or low.
We had no spare parts to support this standard.
The only option was to run the standard open loop.
Over a period of two hours, I had the
All this talk of Instrument BASIC brings up a question. Is the Windows
version "out there" somewhere? I know you can't buy it any more.
Joe Gray
W5JG
On Sun, Feb 28, 2016 at 5:11 PM, Daun Yeagley wrote:
> Hi Magnus
>
> My memory is a bit faded on this, but the Instrument
Pete Lancashire wrote:
... I was using an HP lab supply>>>
Model ? Age ?
My bench has some pretty old HP's even Harrison Lab branded supplies.
I
have had to re-cap a few of them.
In a way it is almost a curse how reliable their supplies were. You
always got the V and I you wanted so one
never
On Sun, Feb 28, 2016 at 3:09 PM, Sanjeev Gupta wrote:
> I am reviewing and expanding and for the NTPSec project <
> http://www.ntpsec.org >, a fork of NTP.
>
Apologies, this should have been:
I am reviewing and expanding and documentation for the NTPSec project <
Hi
Except ….
The big steps give you more “thermal shock” on a BT and that slows things down.
Bob
> On Feb 28, 2016, at 7:28 PM, Richard (Rick) Karlquist
> wrote:
>
>
>
> On 2/28/2016 7:01 AM, Bob Camp wrote:
>> Hi
>>
>> It’s not an electrical issue as much as a
Hi Daun,
Lacking the option I did ask the question how to enable or install it.
I think it would be a nice way of doing some things, knowing from
previous experience, and in particular since it seems like it also can
act as a GPIB controller, which is useful when interacting with other
On 2/28/2016 7:01 AM, Bob Camp wrote:
Hi
It’s not an electrical issue as much as a heat issue ….
Before you start, consider that you will be doing something like:
Move trimmer 1 turn CW
Wait 10 minutes
read frequency
Move trimmer 1 turn CW
wait / read
Move trimer 1/2 turn CCW
wait / read
This turned out to be an easy way to run Lady Heather itself (herself ?) on
Linux - it works well under Wine, but identifying the serial port is a
problem. But run Heather with '/ip=localhost' and ser2net to connect to the
USB serial port and all is smooth.
I used the ser2net config line
Hi Magnus
My memory is a bit faded on this, but the Instrument Basic on the 894xx is
pretty useful, and I'd recommend making use of it. Instrument Basic is a
subset of "Rocky Mountain Basic" which was a very useful programming language,
especially for instrument control. "Back in the day", I
Hi
We have at least one example of the spurs being in the 40 to 80 Hz range
“depending”. That strongly suggests that the original analysis is correct and
that it is a spur in the OCXO rather than line noise induced issues in a test
setup.
Bob
> On Feb 28, 2016, at 5:49 PM, Bill Byrom
Jim wrote:
Can you tell what the cut is if you have the blank in front of you?
You can do it directly with x-ray crystallography. Otherwise, you
need to characterize multiple crystal parameters and infer the cut
from those, which may not be particularly accurate.
Best regards,
Charles
Hello Nigel ,
I already have done a similar repair on a 10811, described here:
https://www.febo.com/pipermail/time-nuts/2012-January/062228.html
A comparison of the 10811 manual, p. 8-16 and schematic, let me strongly
assume, that the 10544 has exactly the same type of NTC inside.
This NTC
Hi
Ok a bit more of the story.
It’s easy to simply turn on the device and see how it warms up. Back when it
was made, the
SC did not yet exist. The only thing it could be was a BT. With an X-ray setup
you can absolutely
tell it’s a BT. With the blank and a pair of calipers you can make a
Hi
WWVB and WWV (like any radio uncorrected radio system) has fairly predictable
shifts
associated with the day / night ionosphere. One *could* fix that issue with a
table
based on station location. I do not know of any library of code that does that
already.
The next “layer” of trouble
On 25 Feb 2016, at 9:07 pm, Jim Harman wrote:
> On Thu, Feb 25, 2016 at 1:08 PM, Neil Green wrote:
>
>> I’ve decided to build this:
>>
>> http://www.hackersbench.com/Projects/1Hz/
>
> Good start!
>
> Once you have built it and observed how sensitive
If the spurs are at exactly 60 Hz multiples (not 120 Hz or 180 Hz) and
you are in an area with 60 Hz line power you might have magnetic field
coupling from nearby power transformers. Normal conductive shielding
won't solve this issue, and Mu-Metal or other high permeability low
frequency materials
... I was using an HP lab supply>>>
Model ? Age ?
My bench has some pretty old HP's even Harrison Lab branded supplies. I
have had to re-cap a few of them.
In a way it is almost a curse how reliable their supplies were. You always
got the V and I you wanted so one
never thought about the
On Sun, Feb 28, 2016 at 2:09 AM, Sanjeev Gupta wrote:
>
> Among NTPSec's goals are a smaller, auditable, code-base; hence support for
> receivers last available in the early-1990s is being removed.
>
I'm a bit confused by your question and the responses.
There are (I believe)
Jim,
Why cut it open? It is relatively easy to measure just by power the
oscillator up. Just in this thread is an echo of a discussion we had
many years ago that explains the method.
The temperature curve for AT, BT and SC-cut is known and quite
different, so just measure the heat-up curve
On 2/28/16 7:07 AM, Sanjeev Gupta wrote:
On Sun, Feb 28, 2016 at 9:45 PM, Tim Shoppa wrote:
Support for WWV in ntpd using the wwv_audio refclock is very good and
delivers jitters substantially less than a millisecond. I have been using
this for over a decade.
Thank you.
Could it be microphonic capacitors, or the crystal itself ?
Have you got a big old heavy power supply with a buzzing transformer on
your workbench ?
On Sun, Feb 28, 2016 at 3:04 PM, Daniel Watson
wrote:
> Hi,
>
> I put one in a freezer and measured the current draw. At
Sanjeev Gupta writes:
> that as a result of the change, precision equipment may not be able to
> recover a usable signal from the new modulation scheme, rendering it
> useless for the sub-100 microsec disciplining.
In fact, the new scheme may actually help with accurate ON-TIME
On Sun, Feb 28, 2016 at 03:09:32PM +0800, Sanjeev Gupta wrote:
> I am reviewing and expanding and for the NTPSec project <
> http://www.ntpsec.org >, a fork of NTP.
>
> Among NTPSec's goals are a smaller, auditable, code-base; hence support for
> receivers last available in the early-1990s is
On 2/28/16 6:23 AM, Bob Camp wrote:
Hi
The whole “BT Cut” issue was a big top secret in HP. They spent a lot of time
obscuring
the fact that they used BT’s. The belief was that if any of the other outfits
figured out that
was what they were doing, the competition would have better OCXO’s.
On Sun, Feb 28, 2016 at 10:57 PM, Bob Camp wrote:
> The new WWVB format is troublesome for older gear that looks at carrier
> phase as a source of precision timing. The NTP driver does not do this.
>
> The new WWVB format is fine for any gear that recovers time from the
> AM
On Sun, Feb 28, 2016 at 9:45 PM, Tim Shoppa wrote:
> Support for WWV in ntpd using the wwv_audio refclock is very good and
> delivers jitters substantially less than a millisecond. I have been using
> this for over a decade.
>
Thank you. In particular, WWV, as compared to
Hi,
I put one in a freezer and measured the current draw. At -12*C, it drew
about 320 mA steady state (1.6W).
Dan
On Sat, Feb 27, 2016 at 7:30 PM, Rob Sherwood. wrote:
> The part draws 600 mA during warm-up, and drops to around 230 to 200 mA
> when stabilized.
> Rob
> NC0B
>
>
Hi
Ok, I think we have a bit of a terminology issue here.
The new WWVB format is troublesome for older gear that looks at carrier
phase as a source of precision timing. The NTP driver does not do this.
The new WWVB format is fine for any gear that recovers time from the
AM modulation on the
Hi
It’s not an electrical issue as much as a heat issue ….
Before you start, consider that you will be doing something like:
Move trimmer 1 turn CW
Wait 10 minutes
read frequency
Move trimmer 1 turn CW
wait / read
Move trimer 1/2 turn CCW
wait / read
Move trimmer 1/4 turn CW
wait / read
Move
Hi
The whole “BT Cut” issue was a big top secret in HP. They spent a lot of time
obscuring
the fact that they used BT’s. The belief was that if any of the other outfits
figured out that
was what they were doing, the competition would have better OCXO’s.
Watch the frequency as it turns on. An
Hi Dan
how many of these oscillators have that low freq.hum?
73
KJ6UHN
Alex
On 2/27/2016 6:25 PM, Daniel Watson wrote:
Hi,
Attached is a plot of the output frequency difference from 10MHz during
warm-up. I believe this indicates the crystal is SC cut.
The VREF and EFC pins on the unit do
The part draws 600 mA during warm-up, and drops to around 230 to 200 mA when
stabilized.
Rob
NC0B
-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Camp
Sent: Saturday, February 27, 2016 2:26 PM
To: Discussion of precise time and frequency
Having a diversity of refclocks is important for any real NTP
implementation. There is a strong tendency towards a GPS monoculture and
the implementers must work against it.
Support for WWV in ntpd using the wwv_audio refclock is very good and
delivers jitters substantially less than a
On Sat, 20 Feb 2016 14:56:47 -0500, you wrote:
>I think that there are a lot of unexplored possibilities, but I definitely am
>not convinced that it sets either the inner or outer oven temperature. There
>are simply better ways to do that in production.
Hi Mike,
On the two that I tested, it
Hal,
It depends a lot on the thermistor. As with any component, there are higher
precision models that would be pretty repeatable within a model number, and
cheaper ones that will be somewhat less repeatable. In this case I didn’t have
a specific model number, nor specific nominal/beta values,
Hi,
I am reviewing and expanding and for the NTPSec project <
http://www.ntpsec.org >, a fork of NTP.
Among NTPSec's goals are a smaller, auditable, code-base; hence support for
receivers last available in the early-1990s is being removed.
I have been on this list for some years (thank you),
Mark,
I don’t see that referenced in the documentation, and the frequency adjustment
pot appears to be plastic, but I will compare a non-conductive tool, to a
conductive one to see if it makes a difference.
Nigel
> On Feb 27, 2016, at 19:11, Mark Sims wrote:
>
> Also,
I would have to make the measurement again with the HP supply off.
I have measured my Rubidium and my GPSDO and never seen anything like this
spectra of close-spaced spurious.
I'll send you some more data direct.
Rob
NC0B
-Original Message-
From: time-nuts
40 matches
Mail list logo