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

[Magnus Danielson]

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