[time-nuts] Re: St Veran gravity red-shift misson

[Harlan Stenn]

Happy to host pictures and any of your related blog posts on the NTF 
website, I don't care if it's on the main site or on a separate projects 
page.

H

On 7/18/2023 9:18 AM, Magnus Danielson via time-nuts wrote:
> Jim,
> 
> Thanks for the kind words. I try to keep you updated, and that becomes 
> easier and easier now that much of the clean-up is done. This experiment 
> continues as we travel back, since we need the reference measurements.
> 
> I take photos and share on my Facebook page. Maybe I should collect 
> things on a web-page. Other work is part of the mission, so I just come 
> out of an interview that me and Bruno Bertrand of Observatoir Royal de 
> Belgique did. This is done in cooperation with them and further support 
> from their excelent scientist Pascal du Fraigne.
> 
> Further, we attempt to document things for a film that should become 
> accessable eventually.
> 
> I think it is important to be transparent with the challenges and 
> hurdles. Some of them is unique to a mission like this, but some is as 
> relevant for a static lab. I'm working on software support that I keep 
> updating and aim to improve further as things go more quiet here.
> 
> I've made stupid mistakes due to stress and fatigue, let's identify them 
> for what they are.
> 
> I hope we can provide better info eventually. We have expected to drift 
> 200 ns over this time. We have multilpe ways to measure this. 
> Unfortunatly we lost the calibration before, to characterize the rate of 
> the clock as sea level, so we will do that afterwords.
> 
> The challenge of being part of a Belgic mission is that they force you 
> to drink Belgic beer, if only I like that... (having a good time, as I 
> really enjoy Belgic beers).
> 
> As for mistakes today... none. We have had a day of fooling around, 
> taking photos, preparing and doing interviews. In addition we show the 
> setup for the turists, which is a nice moment in any day. We love teaching.
> 
> Cheers,
> Magnus
> 
> On 2023-07-18 12:19, James Littlefield wrote:
>> Magnus,
>>
>> Being a long time reader of the time nuts list, I am very much
>> enjoying your posts regarding this experiment. The issues with
>> cabling, power, and software are fascinating to follow along. I look
>> forward to your future updates.
>>
>> Best regards,
>>
>> On Tue, Jul 18, 2023 at 1:25 AM Magnus Danielson via time-nuts
>> <time-nuts at lists.febo.com> wrote:
>>> Kit,
>>>
>>> So, with that spirit, I keep updating.
>>>
>>> Life on the observatory base is somewhat different. The power is
>>> delivered from photovoltic panels and stored in a battery bank, water
>>> comes from the melt water of snow. Therefore being restrictive with
>>> energy and water is both encouraged and required. Drinking water each
>>> mission bring up. You leave provisions for the next mission, so there is
>>> a discovery delight in finding what previous mission donated over. Half
>>> the house is for astronomers, and half the house for the housekeeper and
>>> tourists. The tourists provide a source of income, but every day we get
>>> the oppertunity to explain what we do, and it is not an insignificant
>>> part of a mission here. There is also hikers that comes over they day.
>>>
>>> As for experiment, the setup was done in a haste. This also means
>>> accidents happens and cleanup needs to be done. I lost the 12 V bus when
>>> converted failed. Turns out, due to another issue I had, and I am not
>>> proud to say this, a short circuit. Luckily there is a wealth of fuses
>>> (and a wealth of spare fuses). When the more critical parts sorted
>>> itself out, I have been able to debug the 12V side and resurrect the
>>> large pressure sensor and a TICC.
>>>
>>> As we arrived, we where a little too tired, so lifting batteries failed
>>> so I dropped a pair (again not proud), and the connection broke between
>>> the pair. No short circuit and I could quickly secure the connection to
>>> avoid short circuit. I was able to repair the connection and hook the
>>> batteries up to the charger again, so I have full battery capability 
>>> again.
>>>
>>> I've been able to integrate the Victron MPPT charger into the
>>> InfluxDB/Grafana environment. While this sis not very critical when on
>>> base, it will be relevant as we travel down, as that is a more
>>> challenging thing.
>>>
>>> I've been able to make many upgrade to the Grafana environment.
>>>
>>> We have had some initial data from the GNSS processing, and discovered a
>>> 1 ms jump in time, but under that we see cesium noise as we should. We
>>> suspect that this comes from any of a number of sources, for integer 1
>>> ms jumps can exist in receivers and compensated by post-processing
>>> tools. We will start to analyze that. As a caution we took the decision
>>> to synchornize the PPS of the cesium, as a previous failure it was not
>>> initiated but kept. With measurements we felt confident we could take
>>> the disruption and start measure again. The underlying 10 MHz is not
>>> affected.
>>>
>>> As you see, things happens. Maintaining a log of what happend when is
>>> important. Some of these failures was completely avoidable, but lack of
>>> time, stress, tiredness contributed to the process. As the mission
>>> progresses, robustness is improved. Considering that just continuous
>>> operation in a dynamic environment of a car over several days, then
>>> reloading to another car and then reloading into the station and
>>> transport up is challenging, but only once we lost power to cesium, and
>>> that was before it was really critical. We lost logging in GNSS
>>> receivers due to cable errors and power issues. We lost logging in
>>> Raspberry pi due to power issues and not having the time to make things
>>> autostart. Then again, I keep working to improve robustness, provide
>>> fixes and make other improvements.
>>>
>>> I get the oppertunity to learn more about Raspberry Pi environment,
>>> Python, InfluxDB, Grafana and a whole bunch of sensors.
>>>
>>> The aim is to leave tools and knowledge for comming adventures, and as
>>> we do this again, we do it better from start from all we learned this 
>>> time.
>>>
>>> I had also intended to bring a passive hydrogen maser, but it was too
>>> much work remaining, as it had issues and had not locked up. However,
>>> I've built an improved toolset to apply for more devices as well as the
>>> home lab.
>>>
>>> I've written python code to integrate masers and environment sensors and
>>> push into the InfluxDB, this is done using Python. While some is not yet
>>> "clean" in so many aspects, not only me learning Python but also a few
>>> short-cuts that I want to fix later, some stuff has been done pretty OK.
>>> For Grafana, I keep updating things as I learn. I intend to export the
>>> Grafana Dashboards and have them available with the code, so that you
>>> can use both the python code and the Dashboard for your 5071. The
>>> Grafana Dashboard is done in JSON, so that should work well. I need to
>>> parametrize it, because if you have multiple clocks, you want a
>>> dashboard for each clock. I have already prepared so that all data
>>> gathering tags it with both masertype and maser.
>>>
>>> It may sound like a lot, but it is quite small amount of code, but it
>>> helps a lot.
>>>
>>> There is a whole round of other issues such as having udev mapping
>>> device drivers to the right place, and that I need to fix, it's part of
>>> overall robustness. I've done some work, but not enough.
>>>
>>> You only learn by attempting to do something. You only risk failing by
>>> attempting. So far, we had minor failures, but nothing catastrophic.
>>> After arriving to the base, new problems have not arrived at the same
>>> rate or degree of risk. There is not much remaining uphill from here! :)
>>> (The actual peak is a nice little hike we will do)
>>>
>>> We do this not because it is easy, but because we thought it would be
>>> easy! ;-D
>>>
>>> I hope to be able to spend more time on the scientific result data now
>>> that other practical issues pan out.
>>>
>>> The 5071A is humming about just fine. I can see how control loops combat
>>> temperature shifts. Closed loop controls on essentially all parameters
>>> will suppress environmental effects over to phase and frequency. It is
>>> only by exposing it to non-ideal environments that you can see that, and
>>> I've added as much environmental stuff as I could in order to capture as
>>> much data on that as I can, even if this is lower priority and less than
>>> ideal.
>>>
>>> Validation of sensors is a separate topic alone. I've seen temperature
>>> dependences even from calibrated stuff. That will be analyzed.
>>>
>>> Cheers,
>>> Magnus
>>>
>>> On 2023-07-17 05:24, Kit (Kitski) wrote:
>>>> Magnus,
>>>>
>>>> A wonderful word-picture you're painting.  Please keep the messages 
>>>> flowing.
>>>>
>>>> Take care,
>>>>
>>>> Kit
>>>> VK1LL
>>>>
>>>> -----Original Message-----
>>>> From: Magnus Danielson via time-nuts <time-nuts at lists.febo.com>
>>>> Sent: Sunday, July 16, 2023 6:42 PM
>>>> To: Christopher Hoover <ch at murgatroid.com>; Discussion of precise 
>>>> time and frequency measurement <time-nuts at lists.febo.com>
>>>> Cc: Magnus Danielson <magnus at rubidium.se>
>>>> Subject: [time-nuts] Re: St Veran gravity red-shift misson
>>>>
>>>> Dear Christoffer,
>>>>>>> snip
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>>
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-- 
Harlan Stenn <stenn at ntp.org>, part of
http://networktimefoundation.org - be a member!