On 9/26/20 9:33 PM, John Miles wrote:
One consequence of charge retention is that when the input signal is in the
first Nyquist zone, meaning below fLO/2, no net frequency translation occurs in
a sampler. There is no mixing going on, hence no reciprocal mixing either.
The sampler's
Patrick
Great job on the pix. Very helpful.
Interesting in many ways the 4040 appears newer in design then the 4050.
What is different is that in the 4050 the Cs tube multipkliers and such are
in a magnetic shield.
But the RF sections appear very similar.
Noted the ugly cap and you may have more
>
> Re: thermistors
* Stability of the supply/reference voltage.
>
If the reference voltage is also the reference of the ADC, its stability
and precision are much less of a concern, noise will pretty much be the
only issue.
Didier KO4BB
>
___
If one does a ratiometric measurement comparing the voltage drop across the RTD
with the voltage drop across a stable low Tc resistor connected in series with
the RTD the excitation source only needs to be quiet with good short term
stability.
Bruce
> On 29 September 2020 at 07:48 "John
I second the thermistor as the most "bang for the buck" temperature
measurement device.
My applications have not been time-nuts (or volt-nuts for that matter)
quality but even in the °C accuracy range, they are hard to beat.
Didier KO4BB
___
time-nuts
Have made some progress.
Looks like bad caps. Capacitor "CA" is especially naughty.
https://photos.app.goo.gl/Ye91Fv4Nmuj4xb7n8
Pics and measured supply data:
https://photos.app.goo.gl/dNWKyysC1QykCLWc8
https://drive.google.com/file/d/1t1xjyNTbdwY_j7pg5rt_94GTY68R3ZbS/view?usp=drivesdk
Thanks
Hi
Indeed the most stable (long term) standard is a very high end RTD. These
devices have a lot of voodoo
in their design. Even with all that, they still arrive with a note on the box
that reads “ for applications requiring
< 10 mk, re-calibrate before use”. More or less, you *also* need a
Thanks for going easy on me Bob ... a case of more haste, less speed! I
focussed on low long-term drift specs without realising I had turned up a
voltage reference, sorry.
However, I have found some YSI glass encased thermistors that have long-term
drift specs of <10mK at 25C and 75C over a
I checked my 3456A with a Beckman resistance standard box. A 5000 Ohm
resistor is measured as 25.02 degrees Celsius, which is good considering
neither the 3456A or the Beckman have been calibrated in ages.
I have 10 of the Ametherm ACC-003s on order from DigiKey. When they show up
(and if we
Hi
The Rb may or may not have moved onto the walls. The lamp (as designed) may or
may not have a well……
Bob
> On Sep 28, 2020, at 11:35 AM, David C. Partridge
> wrote:
>
> What about using a the hot-air gun technique to migrate the Rb from the walls
> of the lamp back to the well?
>
>
Hi,
Darn, Bob beat me to it! I was going to suggest the AD590 and a suitable
ADC. The ceramic part is relatively small.
https://www.digikey.com/product-detail/en/analog-devices-inc/AD590JF/AD590JF-ND/611802
It's not as small as a thermistor, but not overly large. They have other
packages as
What about using a the hot-air gun technique to migrate the Rb from the walls
of the lamp back to the well?
David
-Original Message-
From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of Bob kb8tq
Sent: 28 September 2020 14:23
To: Discussion of precise time and
Hi
Depending on your setup, a very normal passive power splitter could do the
job quite well. The 8 port Mini Circuits versions show up on eBay for $20 to
$30
(delivered).
Bob
> On Sep 28, 2020, at 4:25 AM, Kevin Rowett wrote:
>
> I’m in need of a GPS distribution amp. Looking at choices
Hi
> On Sep 27, 2020, at 10:19 PM, Stewart Cobb wrote:
>
> I have a Symmetricom* XPRO rubidium which appears to be reaching its end of
> life. The very sparse manual says that it sets a "service" flag when the
> lamp voltage reaches 600 mV. When I got it, that parameter was at about
> 540.
Good morning Kevin-
I use the same HP/Symmetricom units. Another newer brand, which carries
GNSS frequencies, is from GPS Source:
https://www.gpssource.com/collections/gps-splitter
I have even seen some for sale on eBay for better prices used and bought
some myself. Full disclosure I work for
Hal Murray writes:
> What's the lifetime of a modern lead-acid battery that a telco would use?
That's a slightly embarrasing story actually...
The "Round Telco" battery which Bell Labs designed, is virtually
impossible to kill if you have read the manual.
Needless to say, this made
> Real Telco gear runs from -48VDC fed from, literally, tons of lead-acid
> batteries.
I remember from ages ago some comment about telcos using iron rather than
lead. Google finds Edison batteries, nickel-iron. Long life being their
primary feature.
> Answered my own question: Ametherm ACC-003 from Tim Hughesâ 2-02-2019 post
> to
> the HPAK Equipment group (thanks, Tim!).
Thanks.
I poked around a bit. Ametherm's data sheet shows that they make them in
various resistances and also various accuracies. 003 and friends are 5K.
ACC-003
I’m in need of a GPS distribution amp. Looking at choices and what you’d
recommend.
I have a GPS Networking 8 port in service, at one location. Has worked without
any issues.
I need to add a distribution amp at another lab.
Amps I’m considering:
GPS Networkikng
58516A
58536A
Other choices?
On Montag, 28. September 2020 04:19:12 CEST Stewart Cobb wrote:
> I have a Symmetricom* XPRO rubidium which appears to be reaching its end of
> life. The very sparse manual says that it sets a "service" flag when the
> lamp voltage reaches 600 mV. When I got it, that parameter was at about
> 540.
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